Ext.Ajax.request的同步请求实现
Extjs2.x 实现同步方法
Ext.Ajax.request实现同步请求是通过修改ext-base.js中的Ext.lib.Ajax.request来实现同步请求：
/**Adding a synchronous request to the Ext asynchronous only mode of operation.History: coded from Ext 2.2.Additional configs.@param {Object} options@config {Mixed} [sync] include this for a synchronous request*/Ext.lib.Ajax.request = function(method, uri, cb, data, options) { if(options){ var hs = options.headers; if(hs){ for(var h in hs){ if(hs.hasOwnProperty(h)){ this.initHeader(h, hs[h], false); } } } if(options.xmlData){ if (!hs || !hs['Content-Type']){ this.initHeader('Content-Type', 'text/xml', false); } method = (method ? method : (options.method ? options.method : 'POST')); data = options.xmlData; }else if(options.jsonData){ if (!hs || !hs['Content-Type']){ this.initHeader('Content-Type', 'application/json', false); } method = (method ? method : (options.method ? options.method : 'POST')); data = typeof options.jsonData == 'object' ? Ext.encode(options.jsonData) : options.jsonData; } } [color=red]return this["sync" in options ? "syncRequest" : "asyncRequest"](method, uri, cb, data););[/color]//这句制定调用的方法，如果sync传递了就调用syncRequest， 否则调用原来的方法asyncRequest};};/**Synchronous request. @param {Object} method@param {Object} uri@param {Object} callback@param {Object} postData*/Ext.lib.Ajax.syncRequest = function(method, uri, callback, postData){ var o = this.getConnectionObject(); if (!o) { return null; } else { o.conn.open(method, uri, false); if (this.useDefaultXhrHeader) { if (!this.defaultHeaders['X-Requested-With']) { this.initHeader('X-Requested-With', this.defaultXhrHeader, true); } } if(postData && this.useDefaultHeader && (!this.hasHeaders || !this.headers['Content-Type'])){ this.initHeader('Content-Type', this.defaultPostHeader); } if (this.hasDefaultHeaders || this.hasHeaders) { this.setHeader(o); } o.conn.send(postData || null); this.handleTransactionResponse(o, callback); return o; }};async : false, //ASYNC 是否异步( TRUE 异步 FALSE 同步),