How to convert HTML to PDF in Javascript?

var doc = new jsPDF();          
var elementHandler = {
  '#ignorePDF': function (element, renderer) {
    return true;
  }
};
var source = window.document.getElementsByTagName("body")[0];
doc.fromHTML(
    source,
    15,
    15,
    {
      'width': 180,'elementHandlers': elementHandler
    });

doc.output("dataurlnewwindow");

<div id="content">
     <h3>Hello, this is a H3 tag</h3>

    <p>A paragraph</p>
</div>
<div id="editor"></div>
<button id="cmd">generate PDF</button>

// javascript
var doc = new jsPDF();
var specialElementHandlers = {
    '#editor': function (element, renderer) {
        return true;
    }
};

$('#cmd').click(function () {
    doc.fromHTML($('#content').html(), 15, 15, {
        'width': 170,
            'elementHandlers': specialElementHandlers
    });
    doc.save('sample-file.pdf');
});