function roll_over(img_name, img_src) {
   document[img_name].src = img_src;
}

function validate_form() {
    var valid;
    valid=true;
    var valueExists;


    if (document.forms["ContactForm"].Name.value=="") {
        valid=false;
    };
    if (document.forms["ContactForm"].Phone.value=="") {
        valid=false;
    };
    if (document.forms["ContactForm"].Requirements.value=="") {
        valid=false;
    };

    if (valid==false) { 
        alert('Please complete all required fields'); 
    }

    return valid;
}