function checkform() 
{ 

    if (document.feedback.form_sender_name.value == '') {

        // something is wrong 
        alert('The Name field can not be left blank'); 
        return false; 
    } 
	else if (document.feedback.form_comment.value == '') {
        // something else is wrong
		alert('The Comment field can not be left blank');
		return false;
	}

    return true; 
}