function prepToggleButtons() {

// leave the function if getElementById or getElementsByTagName not understood
if (!document.getElementById || !document.getElementsByTagName) return false;

if(!document.getElementById("buttons")) return false;

// need to hide the toc on initial view
// if the user does not have javascript enabled they will still see this panel
if(document.getElementById("doc_view_toc")){
var tocPanel = document.getElementById("doc_view_toc");
tocPanel.style.display = "none";
}
//also new panel - notes needs to be hidden initially

if (document.getElementById("notes_view")) {
var notePanel = document.getElementById("notes_view");
notePanel.style.display = "none";
}

var theButtonBox = document.getElementById("buttons");
var links = theButtonBox.getElementsByTagName("a");

//disableSelection(document.getElementById("doc_view"));
//disableSelection(document.getElementById("doc_view_h1"));

		for (var i=0; i<links.length; i++) {
		links[i].style.cursor = "pointer";
			links[i].onclick = function() {
			// display the doc/toc panel
			showPanel(this);
			return false;
			}
		}

}

function showPanel(myElement) {

// leave the function if getElementById not understood
if (!document.getElementById) return false;

// get the id of the calling anchor tag
var theId = myElement.getAttribute("id");

// get the three panels
if (document.getElementById("doc_view_toc")) {
var tocPanel = document.getElementById("doc_view_toc");
}
if (document.getElementById("doc_view")) {
var docPanel = document.getElementById("doc_view");
}

if (document.getElementById("notes_view")) {
var notesPanel = document.getElementById("notes_view");
}



//need to set up behaviour for links inside toc

if(document.getElementById("doc_view_toc")){
// get all links inside the toc panel 'doc_view_toc'
var tocLinks = tocPanel.getElementsByTagName("a");

for (var i=0; i<tocLinks.length; i++) {
        // attach onclick behaviour to each link in the toc - which hides the toc and opens up the 'doc_view' panel
	tocLinks[i].onclick = function() {
	//switchOnIcons();
       if(tocPanel!=null){
	tocPanel.style.display = "none";
       }
       if(docPanel!=null){
	docPanel.style.display = "block";
       }
	}

}
}
// toggle the panels depending on which has been clicked on
if (theId == "doc") {
//switchOnIcons();
if(tocPanel!=null){
tocPanel.style.display = "none";
}
/*notesPanel.style.display = "none";*/
if(docPanel!=null) {
docPanel.style.display = "block";
}
} else if (theId == "toc") {
//switchOffIcons();
if(tocPanel!=null){
tocPanel.style.display = "block";
}
if (notesPanel!=null) {
notesPanel.style.display = "none";
}
if (docPanel!=null) {
docPanel.style.display = "none";
}
} else {
//switchOffIcons();
if (notesPanel!=null) {
notesPanel.style.display = "block";
}
if(tocPanel!=null){
tocPanel.style.display = "none";
}
if(docPanel!=null) {
docPanel.style.display = "none";
}
}


}

function disableSelection(element) {
    if(element!= null){
    element.onselectstart = function() {
        return false;
    };
    element.unselectable = "on";
    element.style.MozUserSelect = "none";
    element.onmousedown=function(){return false}
    element.style.cursor = "default";
  }
}

// prepToggleButtons is called using addLoadEvent()