function validate( frm ) {

    var returnValue = false;

    if ( BlankField( frm.first_name.value ) ) {
        alert( "Please enter your first name." );
        frm.first_name.focus();
    } else if ( BlankField( frm.last_name.value ) ) {
        alert( "Please enter your last name." );
        frm.last_name.focus();
    } else if ( !ValidEmail( frm.email.value ) ) {
        alert( "Please enter a valid email address." );
        frm.email.focus();
    } else {
        returnValue = true;
        frm.submit.disabled = true;
    }

    return returnValue;
}