function checkContact()
{
	var name = document.getElementById('name');
	var phone = document.getElementById('phone');
	var email = document.getElementById('email');
	var message = document.getElementById('message');
	var emailReg = /^[a-z0-9][a-z0-9\._-]*[a-z0-9]@[a-z0-9][a-z0-9\._-]*\.[a-z]+$/i;
	
	if(name.value == '')
	{
		alert('Please input your name!');
		name.focus();
		return false;
	}
	if(email.value != '' && ! emailReg.test(email.value))
	{
		alert('The email address is not valid, please enter a valid one.');
		email.focus();
		return false;
	}
	if(message.value == '')
	{
		alert('Please input the message!');
		message.focus();
		return false;
	}
	return true;
}