php:
<?php
header(‘sessionStatus:timeOut‘);
//is_ajax
echo $_SERVER[‘HTTP_X_REQUESTED_WITH‘];
html:
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<script type="text/javascript" src="js_class/html5/jquery-1.7.2.js"></script>
<script type="text/javascript">
$(function(){
$.ajax({
url:‘file_exits.php‘,
type:"get",
success:function(res){
alert(res);
},
complete:function(XMLHttpRequest, str){
if(XMLHttpRequest.getResponseHeader("sessionStatus") == "timeOut"){
alert(‘超时了‘);
}
},
});
});
</script>
</head>
<body>
</body>
</html>