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   1  
   2  function Requester()
   3  {
   4      this.action = null;
   5      this.XML = null;
   6      this.commInterface = null;
   7      this.targetId = null
   8      // Initialise XMLHttpRequest object
   9      this.resetXMLHR();
  10  
  11      return true;
  12  }
  13  
  14  
  15  /**
  16   * Check if the XMLHttpRequest object is available 
  17   */
  18  Requester.prototype.isAvailable = function(){
  19      return (this.commInterface == null) ? false : true;
  20  }
  21  
  22  
  23  /* Execute the action which has been associated with the completion of this object */
  24  Requester.prototype.executeAction = function() {
  25      // If XMLHR object has finished retrieving the data
  26      
  27      if (this.commInterface.readyState == 4)    {
  28          // If the data was retrieved successfully
  29          try    {
  30              if (this.commInterface.status == 200)    {
  31                  this.responseText = this.commInterface.requestXML;
  32                  this.action();
  33              }
  34              // IE returns status = 0 on some occasions, so ignore
  35              else if (this.commInterface.status != 0){
  36                  alert("There was an error while retrieving the URL: " + this.commInterface.statusText);
  37              }
  38          }
  39          catch (error){}
  40      }
  41      return true;
  42  }
  43  
  44  
  45  /* Return responseText */
  46  Requester.prototype.getText = function() {
  47      return this.commInterface.responseText;
  48  }
  49  
  50  
  51  /* Return responseXML */
  52  Requester.prototype.getXML = function() {
  53      return this.commInterface.responseXML;
  54  }
  55  
  56  
  57  /* Initialise XMLHR object and load URL */
  58  Requester.prototype.loadURL = function(URL, CGI) {
  59      this.resetXMLHR();
  60      
  61      this.commInterface.open("GET", URL + "?" + CGI);
  62      var e=(document.charset||document.characterSet||'ISO-8859-8-i');
  63      this.commInterface.setRequestHeader("Content-Type", "text/html; charset="+e);
  64      this.commInterface.setRequestHeader('Accept-Charset',e)
  65      this.commInterface.send(null);
  66  
  67      return true;
  68  }
  69  
  70  
  71  /* Turn off existing connections and create a new XMLHR object */
  72  Requester.prototype.resetXMLHR = function() {
  73      var self = this;
  74  
  75      if (this.commInterface != null && this.commInterface.readyState != 0 && this.commInterface.readyState != 4)    {
  76          this.commInterface.abort();
  77      }
  78  
  79      try    {
  80          this.commInterface = new XMLHttpRequest();
  81      }
  82      catch (error) {
  83          try {
  84              this.commInterface = new ActiveXObject("Microsoft.XMLHTTP");
  85          }
  86          catch (error) {
  87              return false;
  88          }
  89      }
  90  
  91      this.commInterface.onreadystatechange = function()    {
  92          self.executeAction();
  93          return true;
  94      };
  95      return true;
  96  }
  97  
  98  /* Assign the function which will be executed once the XMLHR object finishes retrieving data */
  99  Requester.prototype.setAction = function(actionFunction,part) {
 100      this.action = actionFunction;
 101      return true;
 102  }
 103  
 104  
 105  Requester.prototype.setTarget = function(targetId) {
 106      this.targetId = targetId;
 107      return true;
 108  }
 109  
 110  Requester.prototype.getTarget = function() {
 111      return this.targetId;
 112  }