ocument.getElementById(this.id);
  this.image_node = this.node.getElementsByTagName("img")[0];

  if( this.node.getAttribute("aria-checked") == "true") 
     this.image_node.src = "images/checked.gif";
  
  var obj = this; 
  // Add event handlers for checking a checkbox
  browser.addEvent(this.node, "keydown", function(event) {handleCheckboxKeyDownEvent(event, obj); }, false);
  browser.addEvent(this.node, "click",   function(event) {handleCheckboxClickEvent(event, obj); },   false);
  
  // Add event hand