javascript - Exporting multiple divisions in html file to PDF using JSPDF -

i working on requirement need export html file pdf on button click. html file having multiple divisions , have export selected divisions pdf after converting them canvas-image. bit new jspdf , html2canvas libraries, below code working fine single division. please suggest changes in order handle multiple div export pdf.

<button id="btn">generate pdf</button>  <script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script> <script type="text/javascript" src="//cdn.rawgit.com/mrrio/jspdf/master/dist/jspdf.min.js"></script>  <script type="text/javascript" src="//cdn.rawgit.com/niklasvh/html2canvas/0.5.0-alpha2/dist/html2canvas.min.js"></script>  <script type="text/javascript" >  (function(){      var        form = $('.test'),       cache_width = form.width(),       a4  =[ 595.28,  841.89];  // a4 size paper width , height       $('#create_pdf').on('click',function(){       $('body').scrolltop(0);       createpdf();      });      //create pdf      function createpdf(){       getcanvas().then(function(canvas){        var         img = canvas.todataurl("image/png"),        doc = new jspdf({                unit:'px',                 format:'a4'              });                   doc.addimage(img, 'jpeg', 20, 20);              doc.save('techumber-html-to-pdf.pdf');              form.width(cache_width);       });      }       // create canvas object      function getcanvas(){       form.width((a4[0]*1.33333) -80).css('max-width','none');       return html2canvas(form,{           imagetimeout:2000,           removecontainer:true          });       }       }());  </script> </body> </html> 

"test" class name of 1 div in form not able use below code multiple divs