function checkSignup() {
	if(document.getElementById("email_address").value=='')
	{
		alert("Please enter your email address");
		document.getElementById("email_address").focus();
		return false;
	}
	else if(!validate_email(document.getElementById("email_address").value))
	{
		alert("Please enter a valid email address");
		document.getElementById("email_address").focus();
		return false;
	}
	return true;
}

function validate_email(email) {
	allowed = "1234567890qwertyuiop[]asdfghjklzxcvbnm.@-_QWERTYUIOPASDFGHJKLZXCVBNM";
	for(i=0; i < email.length ;i++) 	{
		if(allowed.indexOf(email.charAt(i))<0) 		{
			return (false);
		}	
	}
	if (document.images) {
		re = /(@.*@)|(\.\.)|(^\.)|(^@)|(@$)|(\.$)|(@\.)/;
		re_two = /^.+\@(\[?)[a-zA-Z0-9\-\.]+\.([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$/;
		if (!email.match(re) && email.match(re_two)) {
			return (-1);		
		} 
	}
}