function isEmail(elm) {
    if (elm.value.indexOf("@") == "-1" || elm.value.indexOf(".") == "-1" || elm.value == "")
    return true;
    else return false;
}

function checkData_contactus() {
  	if (document.form_contactus.name.value.length == 0) {
		alert("Please enter your Name. ");
		document.form_contactus.name.focus();
       return false;
	};
	
	if (isEmail(document.form_contactus.email) == true) {
       alert("Please enter a valid Email address.");
		document.form_contactus.email.focus();
       return false;
    };


	if (document.form_contactus.comments.value.length == 0) {
       alert("Please enter your Comments. ");
		document.form_contactus.comments.focus();
       return false;
	};

	return true;
}