function mouse_over (button, image) {
    if (document.images) {
	   document[button].src = image+"_over.jpg";
	}
}

function mouse_leave (button, image) {
    if (document.images) {
	   document[button].src = image+"_up.jpg";
	}
}

function mouse_down  (button, image) {
    if (document.images) {
	   document[button].src = image+"_down.jpg";
	}
}

function mouse_up (button, image) {
    if (document.images) {
	   document[button].src = image+"_over.jpg";
	}
}

function validate_contact () {
    if (document.contactform.firstname.value == null) {
	   Alert ('Please provide a first name');
	}
	else
	if (document.contactform.email.value == null) {
	   Alert ('Please provide an email address');
	}
	else {
	   document.contactform.submit();
	}
}

function OpenWindow (url) {
   handle=window.open (url,'Brochure','toolbar=no,resizable=yes,scrollbars=yes');
}