JqGrid无法显示，不进入ashx

Question

把JqGrid写到js里面，前面有一块代码也调用了这个js，可以显示纪录，也可以进入HistoryService.ashx里面，断点可以停，但是另外一个调用的时候，不进入HistoryService.ashx，断点不停。请问有人知道是怎么回事吗？

<div style="position:absolute; z-index:9999;"><table  align="left" cellpadding="0" cellspacing="0" border="0"><tr> <td>    <div id="jqgrid" style="border: solid 0px red; text-align: center; width: 920px; "> <table id="list1">  </table> <div id="pager1">  </div> </div>  </td> </tr>   </table></div><iframe style="position:absolute; width:100%; height:100%;z-index:1;"></iframe>
 function GetResult() {
js：
    $("#list1").GridUnload();

    var StationID = $("#hf_BusinessStation").val();
    var ExitTime = $("#hf_BusinessTime").val();
    var VehicleLicense = $("#hf_VehicleLicense").val();

    jQuery("#list1").jqGrid({
        url: '../HistoryService.ashx?StationID=' + StationID + "&ExitTime=" + ExitTime + "&VehicleLicense=" + VehicleLicense + "&random=" + new Date(),
        datatype: "json",
        colNames: ['类型', '出时间', '出车道', '入口站', '入口时间', '入车道', '过江通道', '卡号', '车型', '金额', "支付", "事件"],
        colModel: [

                        { name: 'LaneTypeName', index: 'LaneTypeName', width: 40, align: 'center', editable: false, editoption: { readonly: true} },
                        { name: 'ExitTime', index: 'ExitTime', width: 150, align: 'center', hidden: false, editable: true, editoption: { readonly: true} },
                        { name: 'ExitLane', index: 'ExitLane', width: 50, align: 'center', hidden: false, editable: true, editoption: { readonly: true} },
                        { name: 'EntryStation', index: 'EntryStation', width: 80, align: 'center', editable: false, editoption: { readonly: true} },
                        { name: 'EntryTime', index: 'EntryTime', width: 150, align: 'center', hidden: false, editable: false, editoption: { readonly: true} },
                        { name: 'EntryLane', index: 'EntryLane', width: 50, align: 'center', editable: false, editoption: { readonly: true} },
                        { name: 'ComputeStation', index: 'ComputeStation', width: 60, align: 'center', editable: false, editoption: { readonly: true} },
                        { name: 'CardID', index: 'CardID', width: 100, align: 'center', editable: false, editoption: { readonly: true} },
                        { name: 'VehicleClassName', index: 'VehicleClassName', width: 40, align: 'center', editable: false, editoption: { readonly: true} },
                        { name: 'TotalToll', index: 'TotalToll', width: 60, align: 'center', editable: false, editoption: { readonly: true} },
                        { name: 'PayMethodName', index: 'PayMethodName', width: 160, align: 'center', editable: false, editoption: { readonly: true} },
                        { name: 'InputTypeName', index: 'InputTypeName', width: 100, align: 'center', editable: false, editoption: { readonly: true} }
                    ],
        rowNum: 12,
        rowList: [10, 20, 30],
        pager: '#pager1',
        sortname: 'ExitTime',
        viewrecords: true,
        sortorder: "desc",
        height: "360",
        width: "920",
        shrinkToFit: false,
        autoScroll: false


        //loadonce: true
    });

}