function emailCheck(emailstr){ 
var emailPat = /^[A-Za-z0-9_\-]+([.][A-Za-z0-9_\-]+)*[@][A-Za-z0-9_\-]+([.][A-Za-z0-9_\-]+)+$/
var matchArray = emailstr.match(emailPat);
if (matchArray==null) {
	alert("Please enter a valid Email address.");
	return false;
}
else
{
return true;
}
}