精通js裡的完整ajax代碼

if (typeof XMLHttpRequest == 'undefined') {XMLHttpRequest = function() {return new ActiveXObject(navigator.userAgent.indexOf('MSIE 5') > 0 ? 'Microsoft.XMLHTTP': 'Msxml2.XMLHTTP');}};/*一個完整的ajax函數*/function ajax(options) {options = {type: options.type || 'POST',ulr: options.url || '',timeout: options.timeout || 5000,//設定逾時onComplete: options.onComplete ||function() {},onError: options.onError ||function() {},onSuccess: options.onSuccess ||function() {},data: options.data || ''};var xml = new XMLHttpRequest();xml.open(options.type, options.url, true);var timeoutLength = options.timeout;var requestDone = false;setTimeout(function() {requestDone = true;},timeoutLength);xml.onreadystatechange = function() {if (xml.readyState == 4 && !requestDone) {if (httpSuccess(xml)) {options.onSuccess(httpData(xml, options.type));} else {options.onError();}options.onComplete();xml = null;}};xml.send();/*判斷載入是否成功*/function httpSuccess(r) {try {return ! r.status && location.protocl == 'file:' || (r.status >= 200 && r.status < 300) || r.status == 304 || navigator.userAgent.indexOf('Safari') >= 0 && typeof r.status == 'undefined';} catch(e) {}return false;};/*判斷負載檔案類型*/function httpData(r, type) {var ct = r.getResponseHeader('content-type');var data = !type && ct && ct.indexOf('xml') >= 0;data = tpye == 'xml' || data ? r.responseXML: r.responseText;if (type == 'script') {eval.call(window, data);}return data;}}