jQuery Ajax调用从JSF页面返回xhr.status = 0和thrownError = No Transport

Question

jQuery Ajax调用返回xhr.status = 0并且thrownError =没有来自JSF页面的传输。

我的代码：

    $.ajax({
      type: 'GET',            
        url : urlbcat,
        contentType: "application/json;charset=utf-8",
        dataType: "json",
        success: function(data){
        alert("success "+data.Some_ID);
        CALLINGMETHOD(data);
        }, 
        error: function(xhr, ajaxOptions, thrownError)
        {
            alert("xhr: "+xhr.status);
            alert("thrownError: "+thrownError);
            alert("ajaxOptions: "+ajaxOptions);

        }   


    });

我看到警告显示正确的网址，但是xhr = 0并且thrownError =没有传输