function checkEmail(){
	httpObject = getHTTPObject();
	if (httpObject != null) {
		if (!document.getElementById('email').value== ""){
			httpObject.open("GET", "validate_email.php?email="+document.getElementById('email').value, true);
			httpObject.send(null);
			httpObject.onreadystatechange = setImage;
		}
		else
		{
			document.getElementById('emailflag').innerHTML = "<img src=\"images/mail_invalide.png\">";
		}
	}
}
function getHTTPObject(){
if (window.ActiveXObject) return new ActiveXObject("Microsoft.XMLHTTP");
else if (window.XMLHttpRequest) return new XMLHttpRequest();
else {
alert("Your browser does not support AJAX.");
return null;
}}
function setImage(){
if(httpObject.readyState == 4){
document.getElementById('emailflag').innerHTML = httpObject.responseText;
}}