// JavaScript Document
	String.prototype.trim = function() 
	{
	 // skip leading and trailing whitespace
	 // and return everything in between
	  var x=this;
	  x=x.replace(/^\s*(.*)/, "$1");
	  x=x.replace(/(.*?)\s*$/, "$1");
	  return x;
	}
	
	function processResponse()
	{
		if (req.readyState == 4) 
		{
			var obj = document.getElementById("center");
        	if (req.status == 200) 
			{
				obj.innerHTML = "<div class=\"content\">" + req.responseText + "</div>";
				obj.setAttribute("tabIndex", 1);
				obj.focus();				
        	} 
			else 
			{
				obj.innerHTML = "<div class=\"content\"> <h1>Error</h1><h2>Unable to retrieve data</h2> </div>";
			}
    	}
	}
	
	function addCommentToArticle()
	{
		var form = document.comments_form;
		var articlelink = form.filename.value;		
		
		var data="post=post";
		
		var author = form.author.value;
		if(author)
			data += "&author=" + author.trim();
			
		var email = form.email.value;
		if(email)
			data += "&email=" + email.trim();
			
		var form_url = form.url.value;
		if(form_url)
			data += "&url=" + form_url.trim();
			
		var text = form.text.value;
		if(text)
			data += "&text=" + text.trim();
		
		var url=url_js + "/code/postcomment-ajax.php" + articlelink;	
		if (window.XMLHttpRequest) 
		{
        	req = new XMLHttpRequest();
    	} 
		else if (window.ActiveXObject) 
		{
        	req = new ActiveXObject("Microsoft.XMLHTTP");
    	}
    	req.onreadystatechange = processResponse;
    	req.open("POST", url);
		req.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
	    req.send(data);
	}
	function showArticle(articleID)
	{
		// following code to split and rejoin is needed to ensure leading zeroes of month, day are preserved
		var date_array=articleID.split("/");
		var article_link="";
		if(date_array[0])  // year is present
			article_link += date_array[0];
		if(date_array[1]) // month is present
			article_link += "/" + date_array[1];
		if(date_array[2]) // day is present
			article_link += "/" + date_array[2];
		var url=url_js + "/code/articles-ajax.php/" + article_link;	
		if (window.XMLHttpRequest) 
		{
        	req = new XMLHttpRequest();
    	} 
		else if (window.ActiveXObject) 
		{
        	req = new ActiveXObject("Microsoft.XMLHTTP");
    	}
    	req.onreadystatechange = processResponse;
    	req.open("GET", url, true);
    	req.send(null);
	}
	function showCategory(ctgry)
	{
		var url=url_js + "/code/categories-ajax.php/" + ctgry;
		if (window.XMLHttpRequest) 
		{
        	req = new XMLHttpRequest();
    	} 
		else if (window.ActiveXObject) 
		{
        	req = new ActiveXObject("Microsoft.XMLHTTP");
    	}
    	req.onreadystatechange = processResponse;
    	req.open("GET", url, true);
    	req.send(null);
	}