js 生产 pdf

function saveImageToPdf(idOfHtmlElement)
{
   var fbcanvas = document.getElementById(idOfHtmlElement);
   html2canvas($(fbcanvas),
        {

            onrendered: function (canvas) {

                var width = canvas.width;
                var height = canvas.height;
                var millimeters = {};
                millimeters.width = Math.floor(width * 0.264583);
                millimeters.height = Math.floor(height * 0.264583);

                var imgData = canvas.toDataURL(
                    'image/png');
                var doc = new jsPDF("p", "mm", "a4");
                doc.deletePage(1);
                doc.addPage(millimeters.width, millimeters.height);
                doc.addImage(imgData, 'PNG', 0, 0);
                doc.save('WebSiteScreen.pdf');
            }
        });
}

<script type="text/javascript" src="./js/jsPdf.debug.js"></script>
<script type="text/javascript">
      var downPdf = document.getElementById("renderPdf");
      downPdf.onclick = function() {
          html2canvas(document.body, {
              onrendered:function(canvas) {

                  //返回图片dataURL，参数：图片格式和清晰度(0-1)
                  var pageData = canvas.toDataURL('image/jpeg', 1.0);

                  //方向默认竖直，尺寸ponits，格式a4[595.28,841.89]
                  var pdf = new jsPDF('', 'pt', 'a4');

                  //addImage后两个参数控制添加图片的尺寸，此处将页面高度按照a4纸宽高比列进行压缩
                  pdf.addImage(pageData, 'JPEG', 0, 0, 595.28, 592.28/canvas.width * canvas.height );

                  pdf.save('stone.pdf');

              }
          })
      }
</script>