javascript跨域请求包装函数与用法示例

// 定义AJAX跨域请求的JSON (function(){ if(typeof window.$JSON== 'undefined'){ window.$JSON= {}; }; $JSON._ajax = function(config){ config = config[0] || {}; this.url = config.url || ''; this.type = config.type || 'xhr'; this.method = (this.type == 'json') ? 'GET' : config.method.toUpperCase() || 'GET'; this.param = config.param || null; this.callback = config.callback || {}; this.XHR = null; if(typeof window._$JSON_callback == 'undefined'){ window._$JSON_callback = {}; } this._createRequest(); }; $JSON._ajax.prototype = { // 缓存XHR请求，再次再调用时不再进行判断 _createXHR : function(){ var methods = [ function(){ return new XMLHttpRequest(); }, function(){ return new ActiveXObject('Msxml2.XMLHTTP'); }, function(){ return new ActiveXObject('Microsoft.XMLHTTP'); } ]; for(var i = 0, l = methods.length; i < l; i++){ try{ methods[i](); }catch(e){ continue; } this._createXHR = methods[i]; return methods[i](); } }, // 建立XHR请求 _createRequest : function(){ return (this.type == 'json') ? this._setJSONRequest() : this._setXHRRequest(); }, _setXHRRequest : function(){ var _this = this; var param = ''; for(var i in this.param){ if(param == ''){ param = i+'='+this.param[i]; }else{ param+= '&'+i+'='+this.param[i]; } } this.XHR = this._createXHR(); this.XHR.onreadystatechange = function(){ if(_this.XHR.readyState == 4 && _this.XHR.status == 200){ _this.callback.success(_this.XHR.responseText); }else{ _this.callback.failure('重新操作'); } }; this.XHR.open(this.method, this.url, true); this.XHR.setRequestHeader("Content-Type","application/x-www-form-urlencoded; charset=utf-8"); this.XHR.send(param); }, // 建立JSON请求 _setJSONRequest : function(){ var head = document.getElementsByTagName('head')[0]; var script = document.createElement('script'); var fun = this._setRandomFun(); var _this = this; var param = ''; for(var i in this.param){ if(param == ''){ param = i+'='+this.param[i]; }else{ param+= '&'+i+'='+this.param[i]; } } script.type = 'text/javascript'; script.charset = 'utf-8'; if(head){ head.appendChild(script); }else{ document.body.appendChild(script); } // data：为回调函数所需要传入的参数 // 定义页面中的回调函数，如例子中的"jsonpCallback()"方法 window._$JSON_callback[fun.id] = function(data){ _this.callback.success(data); setTimeout(function(){ delete window._$JSON_callback[fun.id]; script.parentNode.removeChild(script); }, 100); }; script.src = this.url+'?callback='+fun.name+'&'+param; }, // 生成随机JSON回调函数 _setRandomFun : function(){ var id = ''; do{ id = '$JSON'+Math.floor(Math.random()*10000); }while(window._$JSON_callback[id]) return{ id : id, name : 'window._$JSON_callback.'+id } } }; window.$JSON.ajax = function(){ return new $JSON._ajax(arguments); } })();

二、调用方式

//调用方式 var ajax = new $JSON.ajax({ url : 'http://www.sina.com/api', type : 'json', method : 'get', param: { bar: true }, callback : { success : function(data){ console.log( '55668',data); }, failure : function(error){ alert(errow); } } });

更多关于JavaScript相关内容感兴趣的读者可查看本站专题：《JavaScript中ajax操作技巧总结》、《JavaScript切换特效与技巧总结》、《JavaScript查找算法技巧总结》、《JavaScript动画特效与技巧汇总》、《JavaScript错误与调试技巧总结》、《JavaScript数据结构与算法技巧总结》、《JavaScript遍历算法与技巧总结》及《JavaScript数学运算用法总结》