// Function which swaps display between tabs
      var sectionName = "A3";
      
    window.onload=function(){
    	try {
    		if (tocNodeID === undefined)	{
   				var offset = document.getElementById('offset_loc').offsetTop;
    			}
    		else {
    			tocSelectNode(tocNodeID);
    			var offset = document.getElementById('p_' + tocNodeID).offsetTop;
				}
    		
    		}
    	catch(err) {/* Do Nothing */}
    	
        divHeight('leftscroll');
        // scroll the TOC pane to have the current page visible
        try{
            //var offset = document.getElementById('p_' + tocNodeID).offsetTop;
           
            if (offset > 300) {offset = offset - 250;}
            	else {offset = 0;}
            
            document.getElementById('leftscroll').scrollTop = offset;
            }
        catch(err) {/* Do Nothing */}
        document.getElementById('leftscroll').style.visibility = 'visible';
        }
    //window.onresize = function(){
        //divHeight('leftscroll');
    //    }
    //window.onscroll = function(){
        //does not fire in netscape
        //divHeight('leftscroll');
     //   }
      
      function changeTab (tabID) {
      if (isvalidTab(tabID))
      {
          // toggle the tab divs
          document.getElementById('tab_about').style.display = 'none';
          document.getElementById('tab_toc').style.display = 'none';
          document.getElementById('tab_index').style.display = 'none';
          
          document.getElementById('tab_'+tabID).style.display = 'block';

          // toggle the tab images
          if (document.getElementById('tabnav_about')!=undefined)
            {document.getElementById('tabnav_about').className = '';}
          if (document.getElementById('tabnav_toc')!=undefined)
            {document.getElementById('tabnav_toc').className = '';}
          if (document.getElementById('tabnav_index')!=undefined)
            {document.getElementById('tabnav_index').className = '';}

          document.getElementById('tabnav_'+tabID).className = 'current';
        }
      }
      
      function isvalidTab (tabID) {
        if (tabID == 'about' || tabID == 'toc' || tabID == 'index'  )  {
            return true; }
          else { return false; }
      }

/* ************************************************************
/* Expand / Collapsing TOC entries
/* tocToggle expands collapsed TOC sections and collapses expanded
/* sections when called.  Called by clicking on the + or - icon at
/* the left of a TOC entry. 
/* Parameters:
/* element:  the <img> html tag of the clickable icon
/* blockid:  the id value of the <div> tag containing the TOC
/*           section to be toggled.
/* ***********************************************************  */
    function tocToggle(element,blockid) {
    //alert(element.src);
    //alert(element.className);
    //alert(blockid);
    
        if (element.className == 'collapse') {
            // Collapse the block and reset toggle to expand
            element.className = 'expand'
            element.src = '/images/elements/expand_icon.gif'
            document.getElementById(blockid).style.display = 'none';
            }
        else {
            // Expand the block and reset toggle to collapse
            element.className = 'collapse'
            element.src = '/images/elements/collapse_icon.gif'
            document.getElementById(blockid).style.display = 'block';
            }
    
    }

/* ************************************************************
/* Expand / Collapsing TOC entries
/* tocToggle expands collapsed TOC sections and collapses expanded
/* sections when called.  Called by clicking on the + or - icon at
/* the left of a TOC entry. 
/* Parameters:
/* element:  the <img> html tag of the clickable icon
/* blockid:  the id value of the <div> tag containing the TOC
/*           section to be toggled.
/* ***********************************************************  */
    function tocSelectNode(pageid) {
    	//alert(pageid);
    	var selectNode = document.getElementById('p_' + pageid);
    	//alert(window.navigator.appName);
     	selectNode.className = 'leftnavon';
     	// Send the UL node containing this entry to the expand tree function
     	expandTree(selectNode.parentNode.parentNode);
     	}
     	
     function expandTree(ulNode)  {
     	var lnkNode
     	var nextParent
     	//alert('h:' + ulNode.tagName);
     		//alert('ps:' + ulNode.previousSibling.tagName);
     	if (ulNode.tagName == 'UL')  {
     		//alert(ulNode.previousSibling.tagName);
     		if (window.navigator.appName == 'Netscape') {
     			lnkNode = ulNode.previousSibling;
     			nextParent = ulNode.parentNode;
     			}
     		else {
     			lnkNode = ulNode.parentNode;
     			nextParent = ulNode.parentNode.parentNode;
     			}
     		if(lnkNode) {
	     		if (lnkNode.tagName == 'LI') {
		     	    ulNode.style.display = 'block';
		            var toggleImg = lnkNode.getElementsByTagName('img');
		            if (toggleImg.length > 0) {
		               	toggleImg[0].className = 'collapse';
		            	toggleImg[0].src = '/images/elements/collapse_icon.gif';
		     			}
		  			expandTree(nextParent);  	
		     		}
	     		}
     		}
            
    	}
/*scrolling TOC
Resizes the Table of Contents div "leftscroll" when user drags window frame or scrolls main window, and adds scrollbar when needed.

size is calculated based on height of the window opening, the vertical offset of the toc div (plus it's parent div if needed) and the amount of the page that has scrolled.
A max value is determined by getting the height of the main content div "content2"

note: netscape does not support the onscroll event so the div will be sized according to the window opening but will not "stick to the bottom" as the main page is scrolled.


*/

function divHeight(a) {
var myHeight = 200;

if (document.getElementById(a)) {
	var myContentHeight = document.getElementById('content2').offsetHeight;
		document.getElementById(a).style.height=myContentHeight+"px";  // added to always set the toc column to size of content
		/*	if( typeof( window.innerHeight ) == 'number' ) {
    			//not IE
					myHeight = window.innerHeight;
					var myOffset = document.getElementById(a).offsetTop;
					var myPageOffset = window.scrollY;			
					tocHeight = (myHeight+myPageOffset)-myOffset;
  			} else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
    			//IE 6+ 					
					myHeight = document.documentElement.clientHeight;
					var myParent = document.getElementById(a).offsetParent.offsetTop;
					var myOffset = document.getElementById(a).offsetTop;
					var myPageOffset = document.documentElement.scrollTop;
					tocHeight = (myHeight+myPageOffset)-(myOffset+myParent);									
  			} else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
				//older IE
					myHeight = document.body.clientHeight;
					var myParent = getElementById(a).offsetParent.offsetTop;;
					var myOffset = document.getElementById(a).offsetTop; 
				    var myPageOffset = document.body.scrollTop;
					tocHeight = (myHeight+myPageOffset)-(myOffset+myParent);
			}
			if(tocHeight <= myContentHeight){
			document.getElementById(a).style.height=tocHeight+"px";
			}
			else{
			tocHeight = myContentHeight;
			document.getElementById(a).style.height=tocHeight+"px";
			} */
			}  
}