function prepareSend()
{
    var form = document.contact_form; // reference to HTML form

    if (form.name.value.length==0) {
	alert("Please enter Your Name.");
	form.name.focus();
	return false;
    }
	if (form.phone.value.length==0) {
	alert("Please enter Your phone number.");
	form.phone.focus();
	return false;
    }
    if (form.email.value.length==0) {
	alert("Please enter Your email address.");
	form.email.focus();
	return false;
    }
}