function checkEmail(email,msg) {
    var filter = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
    if (!filter.test(email.value)) {
        alert('Email Invalid!');
        email.focus;
        msg.style.display="";
        return false;
    }
    else
        msg.style.display="none";
}