用html2canvas截图，图片x轴y轴数据有重影

  function saveImg() {
            html2canvas($('#container'), {
                onrendered: function (canvas) { 
              var myImage = canvas.toDataURL("image/png");
                    $.ajax({
                
                        url: '../submit/AlarmSearch.ashx?type=SaveImg',
                        type: 'post',
                        dataType: 'json',
                        data: {
                            ImageDate: myImage
                        },
                        timeout: 60000,
                        success: function (date) {
                            r = eval("(" + r + ")");
                            if (r.result == "1") {
                                alert("导出成功!");
                            }
                        }
                    });  
                }
            });
          InitGrid_dataOutExcel();
        }