Printing Blank data when it has more data then a4 size

Question

When my div has more data then a4 size page it generates blank PDF . although it is working fine when it has few data(under a4 size)

I have tried some other way but it doesnt print css

 $scope.ConvertToPDF = function () {
            debugger;
            $("#HideMe").hide();

            html2canvas(document.getElementById('exportthis'), {
                onrendered: function (canvas) {
                    var data = canvas.toDataURL();

                    var docDefinition = {
                        content: [{
                            image: data,
                            width: 500,
                            height:5000
                        }]
                    };
                    pdfMake.createPdf(docDefinition).download('TodaysReport' + ".pdf");



                }
            });