js/pz2.js

   1 /*
   2 ** $Id: pz2.js,v 1.70 2008-03-12 11:36:57 jakub Exp $
   3 ** pz2.js - pazpar2's javascript client library.
   4 */
   5
   6 //since explorer is flawed
   7 if (!window['Node']) {
   8     window.Node = new Object();
   9     Node.ELEMENT_NODE = 1;
  10     Node.ATTRIBUTE_NODE = 2;
  11     Node.TEXT_NODE = 3;
  12     Node.CDATA_SECTION_NODE = 4;
  13     Node.ENTITY_REFERENCE_NODE = 5;
  14     Node.ENTITY_NODE = 6;
  15     Node.PROCESSING_INSTRUCTION_NODE = 7;
  16     Node.COMMENT_NODE = 8;
  17     Node.DOCUMENT_NODE = 9;
  18     Node.DOCUMENT_TYPE_NODE = 10;
  19     Node.DOCUMENT_FRAGMENT_NODE = 11;
  20     Node.NOTATION_NODE = 12;
  21 }
  22
  23 // prevent execution of more than once
  24 if(typeof window.pz2 == "undefined") {
  25 window.undefined = window.undefined;
  26
  27 var pz2 = function ( paramArray )
  28 {
  29
  30     // at least one callback required
  31     if ( !paramArray )
  32         throw new Error("Pz2.js: Array with parameters has to be suplied.");
  33
  34     //supported pazpar2's protocol version
  35     this.suppProtoVer = '1';
  36     if (typeof paramArray.pazpar2path != "undefined")
  37         this.pz2String = paramArray.pazpar2path;
  38     else
  39         this.pz2String = "/pazpar2/search.pz2";
  40     this.useSessions = true;
  41
  42     this.stylesheet = paramArray.detailstylesheet || null;
  43     //load stylesheet if required in async mode
  44     if( this.stylesheet ) {
  45         var context = this;
  46         var request = new pzHttpRequest( this.stylesheet );
  47         request.get( {}, function ( doc ) { context.xslDoc = doc; } );
  48     }
  49
  50     this.errorHandler = paramArray.errorhandler || null;
  51
  52     // function callbacks
  53     this.initCallback = paramArray.oninit || null;
  54     this.statCallback = paramArray.onstat || null;
  55     this.showCallback = paramArray.onshow || null;
  56     this.termlistCallback = paramArray.onterm || null;
  57     this.recordCallback = paramArray.onrecord || null;
  58     this.bytargetCallback = paramArray.onbytarget || null;
  59     this.resetCallback = paramArray.onreset || null;
  60
  61     // termlist keys
  62     this.termKeys = paramArray.termlist || "subject";
  63
  64     // some configurational stuff
  65     this.keepAlive = 50000;
  66
  67     if ( paramArray.keepAlive < this.keepAlive )
  68         this.keepAlive = paramArray.keepAlive;
  69
  70     this.sessionID = null;
  71     this.initStatusOK = false;
  72     this.pingStatusOK = false;
  73     this.searchStatusOK = false;
  74
  75     // for sorting
  76     this.currentSort = "relevance";
  77
  78     // where are we?
  79     this.currentStart = 0;
  80     this.currentNum = 20;
  81
  82     // last full record retrieved
  83     this.currRecID = null;
  84
  85     // current query
  86     this.currQuery = null;
  87
  88     //current raw record offset
  89     this.currRecOffset = null;
  90
  91     //timers
  92     this.statTime = paramArray.stattime || 1000;
  93     this.statTimer = null;
  94     this.termTime = paramArray.termtime || 1000;
  95     this.termTimer = null;
  96     this.showTime = paramArray.showtime || 1000;
  97     this.showTimer = null;
  98     this.showFastCount = 4;
  99     this.bytargetTime = paramArray.bytargettime || 1000;
 100     this.bytargetTimer = null;
 101
 102     // counters for each command and applied delay
 103     this.dumpFactor = 500;
 104     this.showCounter = 0;
 105     this.termCounter = 0;
 106     this.statCounter = 0;
 107     this.bytargetCounter = 0;
 108
 109     // active clients, updated by stat and show
 110     // might be an issue since bytarget will poll accordingly
 111     this.activeClients = 1;
 112
 113     // if in proxy mode no need to init
 114     if (paramArray.usesessions != undefined) {
 115          this.useSessions = paramArray.usesessions;
 116         this.initStatusOK = true;
 117     }
 118     // else, auto init session or wait for a user init?
 119     if (this.useSessions && paramArray.autoInit !== false) {
 120         this.init();
 121     }
 122 };
 123
 124 pz2.prototype =
 125 {
 126     //error handler for async error throws
 127    throwError: function (errMsg, errCode)
 128    {
 129         var err = new Error(errMsg);
 130         if (errCode) err.code = errCode;
 131
 132         if (this.errorHandler) {
 133             this.errorHandler(err);
 134         }
 135         else {
 136             throw err;
 137         }
 138    },
 139
 140     // stop activity by clearing tiemouts
 141    stop: function ()
 142    {
 143        clearTimeout(this.statTimer);
 144        clearTimeout(this.showTimer);
 145        clearTimeout(this.termTimer);
 146        clearTimeout(this.bytargetTimer);
 147     },
 148
 149     // reset status variables
 150     reset: function ()
 151     {
 152         if ( this.useSessions ) {
 153             this.sessionID = null;
 154             this.initStatusOK = false;
 155             this.pingStatusOK = false;
 156         }
 157         this.searchStatusOK = false;
 158         this.stop();
 159
 160         if ( this.resetCallback )
 161                 this.resetCallback();
 162     },
 163
 164     init: function ( sessionId )
 165     {
 166         this.reset();
 167
 168         // session id as a param
 169         if ( sessionId != undefined && this.useSessions ) {
 170             this.initStatusOK = true;
 171             this.sessionID = sessionId;
 172             this.ping();
 173         // old school direct pazpar2 init
 174         } else if (this.useSessions) {
 175             var context = this;
 176             var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 177             request.postParams(
 178                 { "command": "init" },
 179                 function(data) {
 180                     if ( data.getElementsByTagName("status")[0]
 181                             .childNodes[0].nodeValue == "OK" ) {
 182                         if ( data.getElementsByTagName("protocol")[0]
 183                                 .childNodes[0].nodeValue
 184                             != context.suppProtoVer )
 185                             throw new Error(
 186                                 "Server's protocol not supported by the client"
 187                             );
 188                         context.initStatusOK = true;
 189                         context.sessionID =
 190                             data.getElementsByTagName("session")[0]
 191                                 .childNodes[0].nodeValue;
 192                         setTimeout(
 193                             function () {
 194                                 context.ping();
 195                             },
 196                             context.keepAlive
 197                         );
 198                         if ( context.initCallback )
 199                             context.initCallback();
 200                     }
 201                     else
 202                         context.throwError('Init failed. Malformed WS resonse.',
 203                                             110);
 204                 }
 205             );
 206         // when through proxy no need to init
 207         } else {
 208             this.initStatusOK = true;
 209         }
 210     },
 211     // no need to ping explicitly
 212     ping: function ()
 213     {
 214         // pinging only makes sense when using pazpar2 directly
 215         if( !this.initStatusOK || !this.useSessions )
 216             throw new Error(
 217             'Pz2.js: Ping not allowed (proxy mode) or session not initialized.'
 218             );
 219         var context = this;
 220         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 221         request.postParams(
 222             { "command": "ping", "session": this.sessionID },
 223             function(data) {
 224                 if ( data.getElementsByTagName("status")[0]
 225                         .childNodes[0].nodeValue == "OK" ) {
 226                     context.pingStatusOK = true;
 227                     setTimeout(
 228                         function () {
 229                             context.ping();
 230                         },
 231                         context.keepAlive
 232                     );
 233                 }
 234                 else
 235                     context.throwError('Ping failed. Malformed WS resonse.',
 236                                         111);
 237             }
 238         );
 239     },
 240     search: function (query, num, sort, filter, showfrom)
 241     {
 242         clearTimeout(this.statTimer);
 243         clearTimeout(this.showTimer);
 244         clearTimeout(this.termTimer);
 245         clearTimeout(this.bytargetTimer);
 246
 247         this.showCounter = 0;
 248         this.termCounter = 0;
 249         this.bytargetCounter = 0;
 250         this.statCounter = 0;
 251
 252         // no proxy mode
 253         if( !this.initStatusOK )
 254             throw new Error('Pz2.js: session not initialized.');
 255
 256         if( query !== undefined )
 257             this.currQuery = query;
 258         else
 259             throw new Error("Pz2.js: no query supplied to the search command.");
 260
 261         if ( showfrom !== undefined )
 262             var start = showfrom;
 263         else
 264             var start = 0;
 265
 266         var searchParams = {
 267             "command": "search",
 268             "query": this.currQuery,
 269             "session": this.sessionID
 270         };
 271
 272         if (filter !== undefined)
 273             searchParams["filter"] = filter;
 274
 275         var context = this;
 276         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 277         request.postParams(
 278             searchParams,
 279             function(data) {
 280                 if ( data.getElementsByTagName("status")[0]
 281                         .childNodes[0].nodeValue == "OK" ) {
 282                     context.searchStatusOK = true;
 283                     //piggyback search
 284                     context.show(start, num, sort);
 285                     if ( context.statCallback )
 286                         context.stat();
 287                     if ( context.termlistCallback )
 288                         context.termlist();
 289                     if ( context.bytargetCallback )
 290                         context.bytarget();
 291                 }
 292                 else
 293                     context.throwError('Search failed. Malformed WS resonse.',
 294                                         112);
 295             }
 296         );
 297     },
 298     stat: function()
 299     {
 300         if( !this.initStatusOK )
 301             throw new Error('Pz2.js: session not initialized.');
 302
 303         // if called explicitly takes precedence
 304         clearTimeout(this.statTimer);
 305
 306         var context = this;
 307         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 308         request.postParams(
 309             { "command": "stat", "session": this.sessionID },
 310             function(data) {
 311                 if ( data.getElementsByTagName("stat") ) {
 312                     var activeClients =
 313                         Number( data.getElementsByTagName("activeclients")[0]
 314                                     .childNodes[0].nodeValue );
 315                     context.activeClients = activeClients;
 316                     var stat = {
 317                         "activeclients": activeClients,
 318                         "hits":
 319                             Number( data.getElementsByTagName("hits")[0]
 320                                         .childNodes[0].nodeValue ),
 321                         "records":
 322                             Number( data.getElementsByTagName("records")[0]
 323                                         .childNodes[0].nodeValue ),
 324                         "clients":
 325                             Number( data.getElementsByTagName("clients")[0]
 326                                         .childNodes[0].nodeValue ),
 327                         "initializing":
 328                             Number( data.getElementsByTagName("initializing")[0]
 329                                         .childNodes[0].nodeValue ),
 330                         "searching":
 331                             Number( data.getElementsByTagName("searching")[0]
 332                                         .childNodes[0].nodeValue ),
 333                         "presenting":
 334                             Number( data.getElementsByTagName("presenting")[0]
 335                                         .childNodes[0].nodeValue ),
 336                         "idle":
 337                             Number( data.getElementsByTagName("idle")[0]
 338                                         .childNodes[0].nodeValue ),
 339                         "failed":
 340                             Number( data.getElementsByTagName("failed")[0]
 341                                         .childNodes[0].nodeValue ),
 342                         "error":
 343                             Number( data.getElementsByTagName("error")[0]
 344                                         .childNodes[0].nodeValue )
 345                     };
 346
 347                     context.statCounter++;
 348                     var delay = context.statTime
 349                         + context.statCounter * context.dumpFactor;
 350
 351                     if ( activeClients > 0 )
 352                         context.statTimer =
 353                             setTimeout(
 354                                 function () {
 355                                     context.stat();
 356                                 },
 357                                 delay
 358                             );
 359                     context.statCallback(stat);
 360                 }
 361                 else
 362                     context.throwError('Stat failed. Malformed WS resonse.',
 363                                         113);
 364             }
 365         );
 366     },
 367     show: function(start, num, sort)
 368     {
 369         if( !this.searchStatusOK && this.useSessions )
 370             throw new Error(
 371                 'Pz2.js: show command has to be preceded with a search command.'
 372             );
 373
 374         // if called explicitly takes precedence
 375         clearTimeout(this.showTimer);
 376
 377         if( sort !== undefined )
 378             this.currentSort = sort;
 379         if( start !== undefined )
 380             this.currentStart = Number( start );
 381         if( num !== undefined )
 382             this.currentNum = Number( num );
 383
 384         var context = this;
 385         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 386         request.postParams(
 387             {
 388                 "command": "show",
 389                 "session": this.sessionID,
 390                 "start": this.currentStart,
 391                 "num": this.currentNum,
 392                 "sort": this.currentSort,
 393                 "block": 1
 394             },
 395             function(data) {
 396                 if ( data.getElementsByTagName("status")[0]
 397                         .childNodes[0].nodeValue == "OK" ) {
 398                     // first parse the status data send along with records
 399                     // this is strictly bound to the format
 400                     var activeClients =
 401                         Number( data.getElementsByTagName("activeclients")[0]
 402                                     .childNodes[0].nodeValue );
 403                     context.activeClients = activeClients;
 404                     var show = {
 405                         "activeclients": activeClients,
 406                         "merged":
 407                             Number( data.getElementsByTagName("merged")[0]
 408                                         .childNodes[0].nodeValue ),
 409                         "total":
 410                             Number( data.getElementsByTagName("total")[0]
 411                                         .childNodes[0].nodeValue ),
 412                         "start":
 413                             Number( data.getElementsByTagName("start")[0]
 414                                         .childNodes[0].nodeValue ),
 415                         "num":
 416                             Number( data.getElementsByTagName("num")[0]
 417                                         .childNodes[0].nodeValue ),
 418                         "hits": []
 419                     };
 420                     // parse all the first-level nodes for all <hit> tags
 421                     var hits = data.getElementsByTagName("hit");
 422                     for (i = 0; i < hits.length; i++)
 423                         show.hits[i] = Element_parseChildNodes(hits[i]);
 424
 425                     context.showCounter++;
 426                     var delay = context.showTime;
 427                     if (context.showCounter > context.showFastCount)
 428                             delay += context.showCounter * context.dumpFactor;
 429                     if ( activeClients > 0 )
 430                         context.showTimer = setTimeout(
 431                             function () {
 432                                 context.show();
 433                             },
 434                             delay);
 435                     global_show = show;
 436                     context.showCallback(show);
 437                 }
 438                 else
 439                     context.throwError('Show failed. Malformed WS resonse.',
 440                                         114);
 441             }
 442         );
 443     },
 444     record: function(id, offset, syntax, handler)
 445     {
 446         // we may call record with no previous search if in proxy mode
 447         if(!this.searchStatusOK && this.useSessions)
 448            throw new Error(
 449             'Pz2.js: record command has to be preceded with a search command.'
 450             );
 451
 452         if( id !== undefined )
 453             this.currRecID = id;
 454
 455         var recordParams = {
 456             "command": "record",
 457             "session": this.sessionID,
 458             "id": this.currRecID
 459         };
 460
 461         this.currRecOffset = null;
 462         if (offset != undefined) {
 463             recordParams["offset"] = offset;
 464             this.currRecOffset = offset;
 465         }
 466
 467         if (syntax != undefined)
 468             recordParams['syntax'] = syntax;
 469
 470         //overwrite default callback id needed
 471         var callback = this.recordCallback;
 472         var args = undefined;
 473         if (handler != undefined) {
 474             callback = handler['callback'];
 475             args = handler['args'];
 476         }
 477
 478         var context = this;
 479         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 480
 481         request.postParams(
 482             recordParams,
 483             function(data) {
 484                 var recordNode;
 485                 var record;
 486                 //raw record
 487                 if (context.currRecOffset !== null) {
 488                     record = new Array();
 489                     record['xmlDoc'] = data;
 490                     record['offset'] = context.currRecOffset;
 491                     callback(record, args);
 492                 //pz2 record
 493                 } else if ( recordNode =
 494                     data.getElementsByTagName("record")[0] ) {
 495                     // if stylesheet was fetched do not parse the response
 496                     if ( context.xslDoc ) {
 497                         record = new Array();
 498                         record['xmlDoc'] = data;
 499                         record['xslDoc'] = context.xslDoc;
 500                         record['recid'] =
 501                             recordNode.getElementsByTagName("recid")[0]
 502                                 .firstChild.nodeValue;
 503                     //parse record
 504                     } else {
 505                         record = Element_parseChildNodes(recordNode);
 506                     }
 507                     callback(record, args);
 508                 }
 509                 else
 510                     context.throwError('Record failed. Malformed WS resonse.',
 511                                         115);
 512             }
 513         );
 514     },
 515
 516     termlist: function()
 517     {
 518         if( !this.searchStatusOK && this.useSessions )
 519             throw new Error(
 520             'Pz2.js: termlist command has to be preceded with a search command.'
 521             );
 522
 523         // if called explicitly takes precedence
 524         clearTimeout(this.termTimer);
 525
 526         var context = this;
 527         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 528         request.postParams(
 529             {
 530                 "command": "termlist",
 531                 "session": this.sessionID,
 532                 "name": this.termKeys
 533             },
 534             function(data) {
 535                 if ( data.getElementsByTagName("termlist") ) {
 536                     var activeClients =
 537                         Number( data.getElementsByTagName("activeclients")[0]
 538                                     .childNodes[0].nodeValue );
 539                     context.activeClients = activeClients;
 540                     var termList = { "activeclients":  activeClients };
 541                     var termLists = data.getElementsByTagName("list");
 542                     //for each termlist
 543                     for (i = 0; i < termLists.length; i++) {
 544                         var listName = termLists[i].getAttribute('name');
 545                         termList[listName] = new Array();
 546                         var terms = termLists[i].getElementsByTagName('term');
 547                         //for each term in the list
 548                         for (j = 0; j < terms.length; j++) {
 549                             var term = {
 550                                 "name":
 551                                     (terms[j].getElementsByTagName("name")[0]
 552                                         .childNodes.length
 553                                     ? terms[j].getElementsByTagName("name")[0]
 554                                         .childNodes[0].nodeValue
 555                                     : 'ERROR'),
 556                                 "freq":
 557                                     terms[j]
 558                                     .getElementsByTagName("frequency")[0]
 559                                     .childNodes[0].nodeValue || 'ERROR'
 560                             };
 561
 562                             var termIdNode =
 563                                 terms[j].getElementsByTagName("id");
 564                             if(terms[j].getElementsByTagName("id").length)
 565                                 term["id"] =
 566                                     termIdNode[0].childNodes[0].nodeValue;
 567                             termList[listName][j] = term;
 568                         }
 569                     }
 570
 571                     context.termCounter++;
 572                     var delay = context.termTime
 573                         + context.termCounter * context.dumpFactor;
 574                     if ( activeClients > 0 )
 575                         context.termTimer =
 576                             setTimeout(
 577                                 function () {
 578                                     context.termlist();
 579                                 },
 580                                 delay
 581                             );
 582
 583                    context.termlistCallback(termList);
 584                 }
 585                 else
 586                     context.throwError('Termlist failed. Malformed WS resonse.',
 587                                         116);
 588             }
 589         );
 590
 591     },
 592     bytarget: function()
 593     {
 594         if( !this.initStatusOK && this.useSessions )
 595             throw new Error(
 596             'Pz2.js: bytarget command has to be preceded with a search command.'
 597             );
 598
 599         // no need to continue
 600         if( !this.searchStatusOK )
 601             return;
 602
 603         // if called explicitly takes precedence
 604         clearTimeout(this.bytargetTimer);
 605
 606         var context = this;
 607         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 608         request.postParams(
 609             { "command": "bytarget", "session": this.sessionID },
 610             function(data) {
 611                 if ( data.getElementsByTagName("status")[0]
 612                         .childNodes[0].nodeValue == "OK" ) {
 613                     var targetNodes = data.getElementsByTagName("target");
 614                     var bytarget = new Array();
 615                     for ( i = 0; i < targetNodes.length; i++) {
 616                         bytarget[i] = new Array();
 617                         for( j = 0; j < targetNodes[i].childNodes.length; j++ ) {
 618                             if ( targetNodes[i].childNodes[j].nodeType
 619                                 == Node.ELEMENT_NODE ) {
 620                                 var nodeName =
 621                                     targetNodes[i].childNodes[j].nodeName;
 622                                 var nodeText =
 623                                     targetNodes[i].childNodes[j]
 624                                         .firstChild.nodeValue;
 625                                 bytarget[i][nodeName] = nodeText;
 626                             }
 627                         }
 628                     }
 629
 630                     context.bytargetCounter++;
 631                     var delay = context.bytargetTime
 632                         + context.bytargetCounter * context.dumpFactor;
 633                     if ( context.activeClients > 0 )
 634                         context.bytargetTimer =
 635                             setTimeout(
 636                                 function () {
 637                                     context.bytarget();
 638                                 },
 639                                 delay
 640                             );
 641
 642                     context.bytargetCallback(bytarget);
 643                 }
 644                 else
 645                     context.throwError('Bytarget failed. Malformed WS resonse.',
 646                                         117);
 647             }
 648         );
 649     },
 650
 651     // just for testing, probably shouldn't be here
 652     showNext: function(page)
 653     {
 654         var step = page || 1;
 655         this.show( ( step * this.currentNum ) + this.currentStart );
 656     },
 657
 658     showPrev: function(page)
 659     {
 660         if (this.currentStart == 0 )
 661             return false;
 662         var step = page || 1;
 663         var newStart = this.currentStart - (step * this.currentNum );
 664         this.show( newStart > 0 ? newStart : 0 );
 665     },
 666
 667     showPage: function(pageNum)
 668     {
 669         //var page = pageNum || 1;
 670         this.show(pageNum * this.currentNum);
 671     }
 672 };
 673
 674 /*
 675 ********************************************************************************
 676 ** AJAX HELPER CLASS ***********************************************************
 677 ********************************************************************************
 678 */
 679 var pzHttpRequest = function ( url, errorHandler ) {
 680         this.request = null;
 681         this.url = url;
 682         this.errorHandler = errorHandler || null;
 683         this.async = true;
 684         this.requestHeaders = {};
 685
 686         if ( window.XMLHttpRequest ) {
 687             this.request = new XMLHttpRequest();
 688         } else if ( window.ActiveXObject ) {
 689             try {
 690                 this.request = new ActiveXObject( 'Msxml2.XMLHTTP' );
 691             } catch (err) {
 692                 this.request = new ActiveXObject( 'Microsoft.XMLHTTP' );
 693             }
 694         }
 695 };
 696
 697 pzHttpRequest.prototype =
 698 {
 699     postParams: function ( params, callback )
 700     {
 701         this.requestHeaders["Content-Type"]="application/x-www-form-urlencoded";
 702         this._send('POST', {}, this.encodeParams(params), callback);
 703     },
 704
 705     get: function ( params, callback )
 706     {
 707         this._send( 'GET', params, '', callback );
 708     },
 709
 710     post: function ( params, data, callback )
 711     {
 712         this._send( 'POST', params, data, callback );
 713     },
 714
 715     load: function ()
 716     {
 717         this.async = false;
 718         this.request.open( 'GET', this.url, this.async );
 719         this.request.send('');
 720         if ( this.request.status == 200 )
 721             return this.request.responseXML;
 722     },
 723
 724     encodeParams: function (params)
 725     {
 726         var sep = "";
 727         var encoded = "";
 728         for (var key in params) {
 729             if (params[key] != null) {
 730                 encoded += sep + key + '=' + encodeURIComponent(params[key]);
 731                 sep = '&';
 732             }
 733         }
 734         return encoded;
 735     },
 736
 737     _send: function ( type, params, data, callback )
 738     {
 739         this.callback = callback;
 740         var context = this;
 741         this.async = true;
 742         this.request.open( type, this._urlAppendParams(params), this.async );
 743         for (var key in this.requestHeaders)
 744             this.request.setRequestHeader(key, this.requestHeaders[key]);
 745         this.request.onreadystatechange = function () {
 746             context._handleResponse();
 747         }
 748         this.request.send(data);
 749     },
 750
 751     _urlAppendParams: function (params)
 752     {
 753         var encodedParams = this.encodeParams(params);
 754         if (encodedParams)
 755             return this.url + "?" + encodedParams;
 756         else
 757             return this.url;
 758     },
 759
 760     _handleResponse: function ()
 761     {
 762         if ( this.request.readyState == 4 ) {
 763             // pick up pazpr2 errors first
 764             if ( this.request.responseXML
 765                 && this.request.responseXML.documentElement.nodeName == 'error'
 766                 && this.request.responseXML.getElementsByTagName("error")
 767                     .length ) {
 768                 var errAddInfo = '';
 769                 if ( this.request.responseXML.getElementsByTagName("error")[0]
 770                         .childNodes.length )
 771                     errAddInfo = ': ' +
 772                         this.request.responseXML
 773                             .getElementsByTagName("error")[0]
 774                             .childNodes[0].nodeValue;
 775                 var errMsg =
 776                     this.request.responseXML.getElementsByTagName("error")[0]
 777                         .getAttribute("msg");
 778                 var errCode =
 779                     this.request.responseXML.getElementsByTagName("error")[0]
 780                         .getAttribute("code");
 781
 782                 var err = new Error(errMsg + errAddInfo);
 783                 err.code = errCode;
 784
 785                 if (this.errorHandler) {
 786                     this.errorHandler(err);
 787                 }
 788                 else {
 789                     throw err;
 790                 }
 791             } else if ( this.request.status == 200 ) {
 792                 this.callback( this.request.responseXML );
 793             } else {
 794                 var err = new Error("Pz2.js: HTTP request error (AJAX). Code: "
 795                             + this.request.status + " Info: "
 796                             + this.request.statusText );
 797                 err.code = 'HTTP';
 798
 799                 if (this.errorHandler) {
 800                     this.errorHandler(err);
 801                 }
 802                 else {
 803                     throw err;
 804                 }
 805             }
 806         }
 807     }
 808 };
 809
 810 /*
 811 ********************************************************************************
 812 ** XML HELPER FUNCTIONS ********************************************************
 813 ********************************************************************************
 814 */
 815
 816 // DOMDocument
 817
 818 if ( window.ActiveXObject) {
 819     var DOMDoc = document;
 820 } else {
 821     var DOMDoc = Document.prototype;
 822 }
 823
 824 DOMDoc.newXmlDoc = function ( root )
 825 {
 826     var doc;
 827
 828     if (document.implementation && document.implementation.createDocument) {
 829         doc = document.implementation.createDocument('', root, null);
 830     } else if ( window.ActiveXObject ) {
 831         doc = new ActiveXObject("MSXML2.DOMDocument");
 832         doc.loadXML('<' + root + '/>');
 833     } else {
 834         throw new Error ('No XML support in this browser');
 835     }
 836
 837     return doc;
 838 }
 839
 840
 841 DOMDoc.parseXmlFromString = function ( xmlString )
 842 {
 843     var doc;
 844
 845     if ( window.DOMParser ) {
 846         var parser = new DOMParser();
 847         doc = parser.parseFromString( xmlString, "text/xml");
 848     } else if ( window.ActiveXObject ) {
 849         doc = new ActiveXObject("MSXML2.DOMDocument");
 850         doc.loadXML( xmlString );
 851     } else {
 852         throw new Error ("No XML parsing support in this browser.");
 853     }
 854
 855     return doc;
 856 }
 857
 858 DOMDoc.transformToDoc = function (xmlDoc, xslDoc)
 859 {
 860     if ( window.XSLTProcessor ) {
 861         var proc = new XSLTProcessor();
 862         proc.importStylesheet( xslDoc );
 863         return proc.transformToDocument(xmlDoc);
 864     } else if ( window.ActiveXObject ) {
 865         return document.parseXmlFromString(xmlDoc.transformNode(xslDoc));
 866     } else {
 867         alert( 'Unable to perform XSLT transformation in this browser' );
 868     }
 869 }
 870
 871 // DOMElement
 872
 873 Element_removeFromDoc = function (DOM_Element)
 874 {
 875     DOM_Element.parentNode.removeChild(DOM_Element);
 876 }
 877
 878 Element_emptyChildren = function (DOM_Element)
 879 {
 880     while( DOM_Element.firstChild ) {
 881         DOM_Element.removeChild( DOM_Element.firstChild )
 882     }
 883 }
 884
 885 Element_appendTransformResult = function ( DOM_Element, xmlDoc, xslDoc )
 886 {
 887     if ( window.XSLTProcessor ) {
 888         var proc = new XSLTProcessor();
 889         proc.importStylesheet( xslDoc );
 890         var docFrag = false;
 891         docFrag = proc.transformToFragment( xmlDoc, DOM_Element.ownerDocument );
 892         DOM_Element.appendChild(docFrag);
 893     } else if ( window.ActiveXObject ) {
 894         DOM_Element.innerHTML = xmlDoc.transformNode( xslDoc );
 895     } else {
 896         alert( 'Unable to perform XSLT transformation in this browser' );
 897     }
 898 }
 899
 900 Element_appendTextNode = function (DOM_Element, tagName, textContent )
 901 {
 902     var node = DOM_Element.ownerDocument.createElement(tagName);
 903     var text = DOM_Element.ownerDocument.createTextNode(textContent);
 904
 905     DOM_Element.appendChild(node);
 906     node.appendChild(text);
 907
 908     return node;
 909 }
 910
 911 Element_setTextContent = function ( DOM_Element, textContent )
 912 {
 913     if (typeof DOM_Element.textContent !== "undefined") {
 914         DOM_Element.textContent = textContent;
 915     } else if (typeof DOM_Element.innerText !== "undefined" ) {
 916         DOM_Element.innerText = textContent;
 917     } else {
 918         throw new Error("Cannot set text content of the node, no such method.");
 919     }
 920 }
 921
 922 Element_getTextContent = function (DOM_Element)
 923 {
 924     if ( typeof DOM_Element.textContent != 'undefined' ) {
 925         return DOM_Element.textContent;
 926     } else if (typeof DOM_Element.text != 'undefined') {
 927         return DOM_Element.text;
 928     } else {
 929         throw new Error("Cannot get text content of the node, no such method.");
 930     }
 931 }
 932
 933 Element_parseChildNodes = function (node)
 934 {
 935     var parsed = {};
 936     var hasChildElems = false;
 937
 938     if (node.hasChildNodes()) {
 939         var children = node.childNodes;
 940         for (var i = 0; i < children.length; i++) {
 941             var child = children[i];
 942             if (child.nodeType == Node.ELEMENT_NODE) {
 943                 hasChildElems = true;
 944                 var nodeName = child.nodeName;
 945                 if (!(nodeName in parsed))
 946                     parsed[nodeName] = [];
 947                 parsed[nodeName].push(Element_parseChildNodes(child));
 948             }
 949         }
 950     }
 951
 952     var attrs = node.attributes;
 953     for (var i = 0; i < attrs.length; i++) {
 954         var attrName = '@' + attrs[i].nodeName;
 955         var attrValue = attrs[i].nodeValue;
 956         parsed[attrName] = attrValue;
 957     }
 958
 959     // if no nested elements, get text content
 960     if (node.hasChildNodes() && !hasChildElems) {
 961         if (node.attributes.length)
 962             parsed['textContent'] = node.firstChild.nodeValue;
 963         else
 964             parsed = node.firstChild.nodeValue;
 965     }
 966
 967     return parsed;
 968 }
 969
 970 /* do not remove trailing bracket */
 971 }