function validate(f){
	var errorlist='';
	var man=document.getElementById('mandatory').value.split(',');
	for (var i=0;i<man.length;i++){
		if (document.getElementById(man[i]).value=='')
		{
			document.getElementById(man[i]).style.background='#f99';
			errorlist+='<li>'+man[i]+' is empty</li>';
		}
	}
	if (!isEmailAddr(document.getElementById('email').value))
	{
		document.getElementById('email').style.background='#f99';
		errorlist+='<li>Your email seems to be invalid</li>';
	}
	if(errorlist=='')
	{
		return true;
	} else {
		var errmsg='<h3 id="errorheader">I encountered the following errors:</h3>';
		errmsg+='<ul>'+errorlist+'</ul>';
		document.getElementById('error').innerHTML=errmsg;
		return false;
	}
}
function isEmailAddr(str) 
{
    return str.match(/^[\w-]+(\.[\w-]+)*@([\w-]+\.)+[a-zA-Z]{2,7}$/);
}