function toggle(div_id) {
	var el = document.getElementById(div_id);
	if ( el.style.display == 'none' ) {	el.style.display = 'block';}
	else {el.style.display = 'none';}
}
function blanket_size(popUpDivVar,h2) {
	if (typeof window.innerWidth != 'undefined') {
		viewportheight = window.innerHeight;
	} else {
		viewportheight = document.documentElement.clientHeight;
	}
	if ((viewportheight > document.body.parentNode.scrollHeight) && (viewportheight > document.body.parentNode.clientHeight)) {
		blanket_height = viewportheight;
	} else {
		if (document.body.parentNode.clientHeight > document.body.parentNode.scrollHeight) {
			blanket_height = document.body.parentNode.clientHeight;
		} else {
			blanket_height = document.body.parentNode.scrollHeight;
		}
	}
	var blanket = document.getElementById('blanket');
	blanket.style.height = blanket_height + 'px';
	var popUpDiv = document.getElementById(popUpDivVar);
	popUpDiv_height=blanket_height/2-h2; ////150 is half popup's height
	popUpDiv.style.top = popUpDiv_height + 'px';
}
function window_pos(popUpDivVar,w2) {
	if (typeof window.innerWidth != 'undefined') {
		viewportwidth = window.innerHeight;
	} else {
		viewportwidth = document.documentElement.clientHeight;
	}
	if ((viewportwidth > document.body.parentNode.scrollWidth) && (viewportwidth > document.body.parentNode.clientWidth)) {
		window_width = viewportwidth;
	} else {
		if (document.body.parentNode.clientWidth > document.body.parentNode.scrollWidth) {
			window_width = document.body.parentNode.clientWidth;
		} else {
			window_width = document.body.parentNode.scrollWidth;
		}
	}
	var popUpDiv = document.getElementById(popUpDivVar);
	window_width=window_width/2-w2;//150 is half popup's width
	popUpDiv.style.left = window_width + 'px';
}
function popup(imagesrc,caption,width,height,livelink) {
	
	if(livelink!=null)
	{
		livelink=' | <a href="'+livelink+'" style="color:green;font-weight:bold;" title="Click to view" target="_blank">Live preview available</a>';	
	} else
	{
		livelink='';	
	}
	var h2=height/2;
	var w2=width/2;
	blanket_size('popUpDiv',h2);
	window_pos('popUpDiv',w2);
	document.getElementById('popUpDiv').style.width=width+"px";
	document.getElementById('popUpDiv').style.height=height+"px";
	document.getElementById('csspopupcaption').innerHTML=caption+livelink;
	document.getElementById('csspopupimage').innerHTML='<img src="'+imagesrc+'" style="border:1px #cccccc solid;">';
	toggle('blanket');
	toggle('popUpDiv');	
}
function closepopup() {
	document.getElementById('blanket').style.display="none";
	document.getElementById('popUpDiv').style.display="none";
}
function verifyform()
{
		var errormessage;
		var name=document.getElementById('name').value;
		var email=document.getElementById('email').value;
		var msg=document.getElementById('message').value;
		errormessage='';
		if(name==''||name==null)
		{
			errormessage+="Opps you forgot to fill in your name\n";
		}
		
		if(email==''||email==null)
		{
			errormessage+="Opps you forgot to fill in your email address\n";
		} else if(email.indexOf("@")=="-1" || email.indexOf(".")=="-1")
		{
			errormessage+="Opps looks like an invalid email address\n";
		}
		
		if(msg==''||msg==null)
		{
			errormessage+="Opps did you forget to fill in the messages?\n";
		}
		if(errormessage!='')
		{
			errormessage+='\nHaving problem? email directly to this email address instead "bih_hao@hotmail.com"';
			alert(errormessage);	
		} else
		{
			document.getElementById('contactform').submit();
		}
}
<!-- // 
var urlAddress="http://www.givemeadesign.com";
var pageName = "Edison singaporean freelance web designer"; 
function addToFavorites() 
{ 
	if (window.external) 
	{ 
		window.external.AddFavorite(urlAddress,pageName);
	} 
	else 
	{ 
		alert("Your browser doesn't support this function. add us manually!\n-Edison\nhttp://www.givemeadesign.com"); 
	} 
} // -->