JavaScript - Jquery - Firebug Gives An Error/warning!

function chapter12_nodeOne() {
    
    //create an element
    var element = document.createElement('input');
    //set some attributes
    element.setAttribute('type', 'button');
    element.setAttribute('value', 'submit');
    //appendd the element into a DIV
    document.getElementById('myDiv').appendChild(element);
    //uses EventUtil to attach an event listener
  (1)  EventUtil.addHandler(element, 'click', function() { alert('added event handler') });
}

var EventUtil = {
    (2)addHandler: function(element, type, handler) {
        //check if the element and the browser support DOM Level 2 event attachment
        //if the user is not browsing with IE
        if (element.addEventListener) {
            element.addEventListener(type, handler, false);
        }
        //if user is browsing with IE
        else if (element.attachEvent) {
            element.attachEvent("on" + type, handler);
        }
        //if user is using a browser that only supports DOM Level 0 event attachment 
        else {
            element["on" + type] = handler;
        }
    },
    
    removeHandler: function(element, type, handler) {
        //check if the element and the browser support DOM Level 2 event attachment
        //if the user is not browsing with IE
        if (element.removeEventListener) {
            element.removeEventListener(type, handler, false);
        }
        //if user is browsing with IE
        else if (element.detachEvent) {
            element.detachEvent("on" + type, handler);
        }
        //if user is using a browser that only supports DOM Level 0 event attachment 
        else {
            element["on" + type] = null;
        }
    },
    
    preventDefault: function(event)
    {
        if(event.preventDefault)
        {
            event.preventDefault();
        }
        else
        {
            event.returnValue = false;
        }
    }
};

		var component = window.location.hash.replace('#', '');
		var component = component.singularize();
		
		alert("The component name is " + component);
		
		
		
		var singularize = function(){
			if(!String.prototype.singularize){
				String.prototype.singularize = function(){
					var context = this;
					result = ((context.charAt(context.length -1, 1) == 's') ? context.substring(0, context.length - 1) : context);
					return result;
				}
			}
		}

 if(proceed) {
	      $.ajax({
		  	type: "POST",
		  	data: "key="+id,
		  	dataType: 'json',
		  	async: true,
		  	url: "<?php echo site_url(); ?>/server/view_serverdet/",
		  	beforeSend: function() {
	        	$('#view_load'+id).show();
	        	$('#view_load'+id).addClass(class);
	  		},
	        complete: function(){
                      	
	        		$('#view_load'+id).hide();
	        	}
	        },
		  	success: function (server_msg) {
		  		if (null == server_msg) {
		  			var warning = "<font color=\"red\">Unable to load server details</font>";
                	$('#view_load'+id).html(warning);
				} else {
					
                       // Working Fine!
                               }

<select id="instance2" name="instance2"> 
<option value="0">All instances</option> 
<option value="1">Item0</option> 
<option value="2">Item1</option> 
<option value="3">Item2</option> 
                     . 
                     . 
                     . 
<option value="23">Item22</option>

{this.nodeType===1&&this.appendChild(a)})},

wrapInner:function(a){if(c.isFunction(a))return this.each(function(b){c(this).wrapInner(a.call(this,b))});return this.each(function(){var b=c(this),d=b.contents();d.length?d.wrapAll(a):b.append(a)})},wrap:function(a){return this.each(function(){c(this).wrapAll(a)})},unwrap:function(){return this.parent().each(function(){c.nodeName(this,"body")||c(this).replaceWith(this.childNodes)}).end()},append:function(){return this.domManip(arguments,true,function(a){this.nodeType===1&&this.appendChild(a)})},

  document.onmouseover = dohighlight;
  document.onmouseout = dohighlightoff;

  var BGCOLOR = "#444444";
  var BORDERCOLOR = "#FF0000";

// Highlight <table> in grey 
  function dohighlight()
  {
    var elem = window.event.srcElement;

    while (elem!=null && elem.tagName!="TABLE")
        elem = elem.parentElement;

    if (elem==null) return;

    if (elem.border==0)
    {
        elem.border = 1;

        // store current values in custom tag attributes
        //
        elem.oldcolor = elem.style.backgroundColor; // store backgroundcolor
        elem.style.backgroundColor = BGCOLOR; // new background color

        elem.oldbordercolor = elem.style.borderColor; // same with bordercolor
        elem.style.borderColor = BORDERCOLOR;

        var rng = document.body.createTextRange();
        rng.moveToElementText(elem);

// Make a red border around <table>
  function dohighlightoff()
  {
    var elem = window.event.srcElement;

    while (elem!=null && elem.tagName!="TABLE")
        elem = elem.parentElement;

    if (elem==null) return;

    if (elem.border==1)
    {
        elem.border = 0;

        // recover values from custom tag attribute values
        elem.style.backgroundColor = elem.oldcolor;
        elem.style.borderColor = elem.oldbordercolor;
    }
  }

<script type="text/javascript">
(function(){
	
	var headers = document.getElementById("sidebar").childNodes;
	for(var i=0; i < headers.length; i++){
			hideElements(headers[i]);
			
			if(headers[i].nodeName == "h1"){
				headers[i].childNodes[0].onclick = function(){
					hideElements(headers[i]);
					this.parentNode.nextSibling.style.display = "block";
					return false;
			}
		}
	}
	
	var hideElements = function(element){
		if(element.nodeName == "UL") element.style.display = "none";	
	}

})();
</script>

	<body>
		<a name="top"></a>
		<div id="masthead">
			<h1>This is the Help Page</h1>
		</div>
		<div id="sidebar">
			<h1><a href="chapter1"> Info</a></h1>
			<ul>
				<li><a href="#section1">Section 1</a></li>
				<li><a href="#section2">Section 2</a></li>
				<li><a href="#section3">Section 3</a></li>
			</ul>
			<h1><a href="chapter2"> Info</a></h1>
			<ul>
				<li><a href="#section4">Section 4</a></li>
				<li><a href="#section5">Section 5</a></li>
				<li><a href="#section6">Section 6</a></li>
			</ul>	
		</div>	
		<div id="content">
			<h1 id="section1">Section 1</h1>
			<p>
			</p>
			<a href="#top">Back to Top</a>	
			<h1 id="section2">Section 2</h1>
			<p>
			</p>
			<a href="#top">Back to Top</a>	
			<h1 id="section3">Section 3</h1>
			<p>
			</p>
			<a href="#top">Back to Top</a>	
		</div>	
	</body>

$(document).ready(function(){
	//References
	var change = $("#menu li a");
	var loading = $("#loading");
	var content = $("#content");
	
	//Manage click events
	change.click(function(){
		//show the loading bar
		showLoading();
		//load selected section
		if(this.id == "home")
		{
			change.load(this.className='current-page');
			content.slideUp();
			content.load("pages/index.php", hideLoading);
			content.slideDown();
		}
		else if(this.id == "secondpage")
		{
			change.load(this.className='current-page');
			content.slideUp();
			content.load("pages/secondpage.php", hideLoading);
			content.slideDown();
		}
		else
		{
			//hide loading bar if there is no selected section
			hideLoading();
		}
	});

	//show loading bar
	function showLoading(){
		loading
			.css({visibility:"visible"})
			.css({opacity:"1"})
			.css({display:"block"})
		;
	}

	//hide loading bar
	function hideLoading(){
		loading.fadeTo(1000, 0);
	};
});

<ul id="menu">
<li><a id="home" class="normal" href="#Home"></a></li>
<li><a id="secondpage" class="normal"  href="#Secondpage"></a></li>		
</ul>

<div id="content">
<ul id="sec-menu">
<li><a id="link1" class="normal" href="#">Link1</a></li>
<li><a id="link2" class="normal"  href="#">Link2</a></li>		
</ul>
</div>

jQuery(document).ready(function($) {
        function load(num) {
            $('#content').load(num +".html");
        }

        $.history.init(function(url) {
                load(url == "" ? "1" : url);
            });

        $('#ajax-links a').live('click', function(e) {
                var url = $(this).attr('href');
                url = url.replace(/^.*#/, '');
                $.history.load(url);
                return false;
            });
    });