代码示例：（标识：eg_js_ajax_callback）
<!DOCTYPE html>
<html>
<body>
<div id="demo">
<h1>XMLHttpRequest 对象</h1>
<button type="button" onclick="loadDoc('/static/demo/txt/ajax_info.txt', myFunction)">更改内容
</button>
</div>
<script>
function loadDoc(url, cFunction) {
var xhttp;
xhttp=new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
cFunction(this);
}
};
xhttp.open("GET", url, true);
xhttp.send();
}
function myFunction(xhttp) {
document.getElementById("demo").innerHTML =
xhttp.responseText;
}
</script>
</body>
</html>
