function valid(id, error_msg, the_default, min_length) {
    var el = document.getElementById(id);
    if( !el ) 
        return true;
    
    if( el.value.length < min_length || el.value == the_default ) {
        alert(error_msg);
        el.focus();
        if( el.value == the_default )
            el.value = '';
        return false;
    }
    
    return true;
}
function check_email(el) {
    var Regex = /^([a-zA-Z0-9_\.\-\+])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;                   
    if( el.value.length <= 1 || !Regex.test(el.value) ) {
        alert('Please enter a valid Email Address.');
        el.focus(); 
        el.value = '';
        return false;
    }

    return true;
}