function check_required_fields() {
    var i = 0;
    var j = 0;
    var Elems;
    var Fld;


    while (i < document.forms.length) {
        Elems = document.forms[i].elements;
        for (j=0;j<Elems.length;j++) {
            Fld = Elems[j];
            //alert(Fld.name.length);
            //alert(Fld.name.substring(0,4));
            if (Fld.name.length >= 4) {
                if (Fld.name.substring(0,4) == 'req_') {
                    if (!Fld.value) {
                        var msg;
                        if (Fld.id) {
                            msg = Fld.id;
                        }
                        else {
                            msg = Fld.name.substring(4,Fld.name.length);
                        }
                        alert(msg + " is a required field, and may not be left blank.");
                        return false;
                    }
                }
            }
        }
        i++;
    }
    return true;
}