樹青兄寫的一個ajax類。
var http_request = false;
function send_request(method,url,formName,responseType,callback) {
?http_request = false;
?var content =""
?if(forName != null)content = getFormAsString(formName);
??
?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("不能創(chuàng)建XMLHttpRequest對象實例.");
??return false;
?}
?if(responseType.toLowerCase()=="text") {
??http_request.onreadystatechange = callback;
?}
?else if(responseType.toLowerCase()=="xml") {
??http_request.onreadystatechange = callback;
?}
?else {
??window.alert("響應(yīng)類別參數(shù)錯誤。");
??return false;
?}
?if(method.toLowerCase()=="get") {
??http_request.open(method, url, true);
?}
?else if(method.toLowerCase()=="post") {
??http_request.open(method, url, true);
??http_request.setRequestHeader("Content-Type","application/x-www-form-urlencoded");??
?}
?else {
??window.alert("http請求類別參數(shù)錯誤。");
??return false;
?}??
?if(window.ActiveXObject) http_request.setRequestHeader("If-Modified-Since", "0");
?http_request.send(content);
}

function getFormAsString(formName){

returnString ="";

formElements=document.forms[formName].elements;

for(var i=formElements.length-1;i>=0; --i ){

returnString+="&"

+escape(formElements[i].name)+"="

+escape(formElements[i].value);

}

}