Ajax模型框架完整代码

<script language=\"javascript\">
var http_request = false;
function send_request(url) {//初始化、指定处理函数、发送请求的函数
http_request = false;
//开始初始化XMLHttpRequest对象
if(window.XMLHttpRequest) { //Mozilla 浏览器
http_request = new XMLHttpRequest();
if (http_request.overrideMimeType) {//设置MiME类别
http_request.overrideMimeType('text/xml');
}
}
else if (window.ActiveXObject) { // IE浏览器
try {
http_request = new ActiveXObject(\"Msxml2.XMLHTTP\");
} catch (e) {
try {
http_request = new ActiveXObject(\"Microsoft.XMLHTTP\");
} catch (e) {}
}
}
if (!http_request) { // 异常，创建对象实例失败
window.alert(\"不能创建XMLHttpRequest对象实例.\");
return false;
}
http_request.onreadystatechange = processRequest;
// 确定发送请求的方式和URL以及是否同步执行下段代码
http_request.open(\"GET\", url, true);
http_request.send(null);
}
// 处理返回信息的函数
function processRequest() {
if (http_request.readyState == 4) { // 判断对象状态
if (http_request.status == 200) { // 信息已经成功返回，开始处理信息
alert(http_request.responseText);
} else { //页面不正常
alert(\"您所请求的页面有异常。\");
}
}
}
</script>
Ajax框架调用:
<script language='javascript'>
function userCheck() {
var f = document.form1;
var username = f.username.value;
if(username==\"\") {
window.alert(\"用户名不能为空。\");
f.username.focus();
return false;
}
else {
send_request('sample1_2.jsp?username='+username);
}
}

</script>