function sendMail() {
	var isValid = false;
	var name = trim(document.getElementById('name').value);
	var email = trim(document.getElementById('email').value);
	var subject = trim(document.getElementById('subject').value);
	var content = trim(document.getElementById('message').value);
	
	if (name=='')
		alert('Please input your name');
	else if (email=='' || !isValidMail(email))
		alert('Please input your E-Mail');
	else if (subject=='')
		alert('Please input the title');
	else if (content=='')
	    alert('Please input the message');
	else //check OK
		isValid = true;
	
	if (isValid)
		return true;
	else
		return false;
}

function trim(str) {
	return str.replace(/^\s+|\s+$/g,"");
}

function isValidMail(mail) {
	var str = mail.replace(/\s/g,"");
	var reg = /^[_.0-9a-z-]+@([0-9a-z][0-9a-z-]+.)+[a-z]/;
	return reg.test(str);
}