AJAX异步传输用到哪些对象？具体实例。

AJAX异步传输用到哪些对象？具体实例。

function ajax(){
this.method;
this.url;
this.responsetype;
this.content;
var http_request = false;
this.getExecObj = function(reValue){
if(window.XMLHttpRequest) {
http_request = new XMLHttpRequest();
if (http_request.overrideMimeType) {
http_request.overrideMimeType(text/xml);
}
}
else if (window.ActiveXObject) {
try {
http_request = new ActiveXObject(Msxml2.XMLHTTP);
} catch (e) {
try {
http_request = new ActiveXObject(Microsoft.XMLHTTP);
} catch (e) {}
}
}
if (!http_request) {
//window.alert(创建XMLHttpRequest对象实例失败.);
return false;
}if(this.method.toLowerCase()==get) {
http_request.open(this.method, this.url, true);
}
else if(this.method.toLowerCase()==post) {
http_request.open(this.method, this.url, true);
http_request.setRequestHeader(Content-Type,application/x-www-form-urlencoded);
}
else {
//......余下全文>>