function check_email(email_id){
	emailRegExp = /^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.([a-z]){2,4})$/;
	var err_mail='Email address incorrect!';
	
		if(emailRegExp.test(document.getElementById(email_id).value)){
			alert('Please press OK to submit your form!');
			return true;
		}else{
			alert(err_mail);
			return false;
		}
}