ajax状态描述
代码
<script>
var s1 = document.getElementById('s1');
s1.onclick = function () {
var hint_info = document.getElementById('hint_info');
var user_name = document.getElementById('user_name');
var xhr = new XMLHttpRequest();
xhr.open('get', 'backend.php?user_name=' + user_name, true);
xhr.send(null);
xhr.onreadystatechange = function () {
if(xhr.readyState == 4 && xhr.status == 200) {
hint_info.innerHTML = '用户名可以使用'
} else {
hint_info.innerHTML = '用户名被注册了'
}
}
}
</script>