ajax与后台数据交互

<span style="font-family:SimHei;font-size:14px;">function dataForjson(url,dataJson) {
    var json;
    $.ajax({
        type: "POST",url: url,获取数据的链接（指向的是WebService.asmx，例如：../webservice/ajaxDecisionService.asmx/selectOperationCount）
        data: dataJson,contentType: "application/json; charset=utf-8",dataType: "json",async: false,//如果要在$.ajax外面获取ajax获取到的值，则ajax必须获得同步
        success: function (msg) {
            json = msg;
        }
    });
    return json;
}</span>