JavaScript ajax请求

var XMLHttpReq;
function createXMLHttpRequest() {
try {
XMLHttpReq = new ActiveXObject("Msxml2.XMLHTTP");//IE高版本创建XMLHTTP
}
catch(E) {
try {
XMLHttpReq = new ActiveXObject("Microsoft.XMLHTTP");//IE低版本创建XMLHTTP
}
catch(E) {
XMLHttpReq = new XMLHttpRequest();//兼容非IE浏览器，直接创建XMLHTTP对象
}
}

}
function sendAjaxRequest(url) {
createXMLHttpRequest();                                //创建XMLHttpRequest对象
XMLHttpReq.open("post", url, true);
XMLHttpReq.onreadystatechange = processResponse; //指定响应函数
XMLHttpReq.send(null);
}
//回调函数
function processResponse() {
if (XMLHttpReq.readyState == 4) {
if (XMLHttpReq.status == 200) {
var text = XMLHttpReq.responseText;

/**
*实现回调
*/
text = window.decodeURI(text);
var cp = document.getElementById("cp");
cp.innerHTML = "";
var values = text.split("|");
for (var i = 0; i < values.length; i++) {
var temp = document.createElement("option");
temp.text = values[i];
temp.value = values[i];
cp.options.add(temp);
}

}
}

}