function isValidEmail(str) {
   return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
 
}
function validate_contact_us() {
	var obj = document.contact_us;
	if(obj.txtName.value == '') {
		alert('Please Enter Your Name.');
		obj.txtName.focus();
		return false;
	}
	if(obj.txtSubject.value == '') {
		alert('Please Enter Subject.');
		obj.txtSubject.focus();
		return false;
	}
	if(obj.txtEnquiry.value == '') {
		alert('Please Enter Message.');
		obj.txtEnquiry.focus();
		return false;
	}
	if(obj.txtEmail.value == '') {
		alert('Please Enter Email.');
		obj.txtEmail.focus();
		return false;
	}
	else {
		if(!isValidEmail(obj.txtEmail.value)) {
			alert('Please Enter Valid Email.');
			obj.txtEmail.focus();
			return false;
		}
	}
	return true;
}