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[转载]ecshop中的Ajax.call定义及讲解_活在当下，展现自我。_百度空间.
在ECShop中，经常看到这样的定义：
Ajax.call(‘api_tb_goods_upload.php?is_ajax=1&&act=get_goods_list’, filters1, queryGoodsResponse , ‘POST’, ‘JSON’);
其中，Ajax.call是ecshop中的非常重要的ajax回调函数。
该函数定义在：
js / transport.js
代码如下：
var Transport =
{
/* *
* 存储本对象所在的文件名。
*
* @static
*/
filename : "transport.js",
/* *
* 存储是否进入调试模式的开关，打印调试消息的方式，换行符，调试用的容器的ID。
*
* @private
*/
debugging :
{
isDebugging : 0,
debuggingMode : 0,
linefeed : "",
containerId : 0
},
/* *
* 设置调试模式以及打印调试消息方式的方法。
*
* @public
* @param {int} 是否打开调试模式 0：关闭，1：打开
* @param {int} 打印调试消息的方式 0：alert，1：innerHTML
*
*/
debug : function (isDebugging, debuggingMode)
{
this.debugging =
{
"isDebugging" : isDebugging,
"debuggingMode" : debuggingMode,
"linefeed" : debuggingMode ? "<br />" : "\n",
"containerId" : "dubugging-container" + new Date().getTime()
};
},
/* *
* 传输完毕后自动调用的方法，优先级比用户从run()方法中传入的回调函数高。
*
* @public
*/
onComplete : function ()
{
},
/* *
* 传输过程中自动调用的方法。
*
* @public
*/
onRunning : function ()
{
},
/* *
* 调用此方法发送HTTP请求。
*
* @public
* @param {string} url 请求的URL地址
* @param {mix} params 发送参数
* @param {Function} callback 回调函数
* @param {string} ransferMode 请求的方式，有"GET"和"POST"两种
* @param {string} responseType 响应类型，有"JSON"、"XML"和"TEXT"三种
* @param {boolean} asyn 是否异步请求的方式
* @param {boolean} quiet 是否安静模式请求
*/
run : function (url, params, callback, transferMode, responseType, asyn, quiet)
{
/* 处理用户在调用该方法时输入的参数 */
params = this.parseParams(params);
transferMode = typeof(transferMode) === "string"
&& transferMode.toUpperCase() === "GET"
? "GET"
: "POST";
if (transferMode === "GET")
{
var d = new Date();
url += params ? (url.indexOf("?") === - 1 ? "?" : "&") + params : "";
url = encodeURI(url) + (url.indexOf("?") === - 1 ? "?" : "&") + d.getTime() + d.getMilliseconds();
params = null;
}
responseType = typeof(responseType) === "string" && ((responseType = responseType.toUpperCase()) === "JSON" || responseType === "XML") ? responseType : "TEXT";
asyn = asyn === false ? false : true;
/* 处理HTTP请求和响应 */
var xhr = this.createXMLHttpRequest();
try
{
var self = this;
/**/
if (typeof(self.onRunning) === "function" && !quiet)
{
self.onRunning();
}
//alert(url);
xhr.open(transferMode, url, asyn);
if (transferMode === "POST")
{
xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
}
if (asyn)
{
xhr.onreadystatechange = function (){
if (xhr.readyState == 4){
switch ( xhr.status ){
case 0:
case 200: // OK!
if (typeof(self.onComplete) === "function"){
self.onComplete();
//alert(1);
}
if (typeof(callback) === "function"){
callback.call(self, self.parseResult(responseType, xhr), xhr.responseText);
//alert(2);
}
break;
case 304: // Not Modified
break;
case 400: // Bad Request
alert("XmlHttpRequest status: [400] Bad Request");
break;
case 404: // Not Found
alert("XmlHttpRequest status: [404] \nThe requested URL "+url+" was not found on this server.");
break;
case 409: // Conflict
break;
case 503: // Service Unavailable
alert("XmlHttpRequest status: [503] Service Unavailable");
break;
default:
alert("XmlHttpRequest status: [" + xhr.status + "] Unknow status.");
}
xhr = null;
}
}
if (xhr != null) xhr.send(params);
}
else
{
/**/
if (typeof(self.onRunning) === "function")
{
self.onRunning();
}
xhr.send(params);
var result = self.parseResult(responseType, xhr);
//xhr = null;
if (typeof(self.onComplete) === "function")
{
self.onComplete();
}
if (typeof(callback) === "function")
{
callback.call(self, result, xhr.responseText);
}
return result;
}
}
catch (ex)
{
if (typeof(self.onComplete) === "function")
{
self.onComplete();
}
alert(this.filename + "/run() error:" + ex.description);
}
},
/* *
* 如果开启了调试模式，该方法会打印出相应的信息。
*
* @private
* @param {string} info 调试信息
* @param {string} type 信息类型
*/
displayDebuggingInfo : function (info, type)
{
if ( ! this.debugging.debuggingMode)
{
alert(info);
}
else
{
var id = this.debugging.containerId;
if ( ! document.getElementById(id))
{
div = document.createElement("DIV");
div.id = id;
div.style.position = "absolute";
div.style.width = "98%";
div.style.border = "1px solid #f00";
div.style.backgroundColor = "#eef";
var pageYOffset = document.body.scrollTop
|| window.pageYOffset
|| 0;
div.style.top = document.body.clientHeight * 0.6
+ pageYOffset
+ "px";
document.body.appendChild(div);
div.innerHTML = "<div></div>"
+ "<hr style='height:1px;border:1px dashed red;'>"
+ "<div></div>";
}
var subDivs = div.getElementsByTagName("DIV");
if (type === "param")
{
subDivs[0].innerHTML = info;
}
else
{
subDivs[1].innerHTML = info;
}
}
},
/* *
* 创建XMLHttpRequest对象的方法。
*
* @private
* @return 返回一个XMLHttpRequest对象
* @type Object
*/
createXMLHttpRequest : function ()
{
var xhr = null;
if (window.ActiveXObject)
{
var versions = ['Microsoft.XMLHTTP', 'MSXML6.XMLHTTP', 'MSXML5.XMLHTTP', 'MSXML4.XMLHTTP', 'MSXML3.XMLHTTP', 'MSXML2.XMLHTTP', 'MSXML.XMLHTTP'];
for (var i = 0; i < versions.length; i ++ )
{
try
{
xhr = new ActiveXObject(versions[i]);
break;
}
catch (ex)
{
continue;
}
}
}
else
{
xhr = new XMLHttpRequest();
}
return xhr;
},
/* *
* 当传输过程发生错误时将调用此方法。
*
* @private
* @param {Object} xhr XMLHttpRequest对象
* @param {String} url HTTP请求的地址
*/
onXMLHttpRequestError : function (xhr, url)
{
throw "URL: " + url + "\n"
+ "readyState: " + xhr.readyState + "\n"
+ "state: " + xhr.status + "\n"
+ "headers: " + xhr.getAllResponseHeaders();
},
/* *
* 对将要发送的参数进行格式化。
*
* @private
* @params {mix} params 将要发送的参数
* @return 返回合法的参数
* @type string
*/
parseParams : function (params)
{
var legalParams = "";
params = params ? params : "";
if (typeof(params) === "string")
{
legalParams = params;
}
else if (typeof(params) === "object")
{
try
{
legalParams = "JSON=" + obj2str(params);
}
catch (ex)
{
alert("Can't stringify JSON!");
return false;
}
}
else
{
alert("Invalid parameters!");
return false;
}
if (this.debugging.isDebugging)
{
var lf = this.debugging.linefeed,
info = "[Original Parameters]" + lf + params + lf + lf
+ "[Parsed Parameters]" + lf + legalParams;
this.displayDebuggingInfo(info, "param");
}
return legalParams;
},
/* *
* 对返回的HTTP响应结果进行过滤。
*
* @public
* @params {mix} result HTTP响应结果
* @return 返回过滤后的结果
* @type string
*/
preFilter : function (result)
{
return result.replace(/\xEF\xBB\xBF/g, "");
},
/* *
* 对返回的结果进行格式化。
*
* @private
* @return 返回特定格式的数据结果
* @type mix
*/
parseResult : function (responseType, xhr)
{
var result = null;
switch (responseType)
{
case "JSON" :
result = this.preFilter(xhr.responseText);
try
{
result = result.parseJSON();
}
catch (ex)
{
throw this.filename + "/parseResult() error: can't parse to JSON.\n\n" + xhr.responseText;
}
break;
case "XML" :
result = xhr.responseXML;
break;
case "TEXT" :
result = this.preFilter(xhr.responseText);
break;
default :
throw this.filename + "/parseResult() error: unknown response type:" + responseType;
}
if (this.debugging.isDebugging)
{
var lf = this.debugging.linefeed,
info = "[Response Result of " + responseType + " Format]" + lf
+ result;
if (responseType === "JSON")
{
info = "[Response Result of TEXT Format]" + lf
+ xhr.responseText + lf + lf
+ info;
}
this.displayDebuggingInfo(info, "result");
}
return result;
}
};
/* 定义两个别名 */
var Ajax = Transport;
Ajax.call = Transport.run;
