Untitled

<head>
<script src="http://cdnjs.cloudflare.com/ajax/libs/html2canvas/0.4.1/html2canvas.min.js"></script>
</head>
<body>
<div id='test'>Take My screenshot</div>
<p>Some other part of html</p>

<button onclick ="ScreenShot()">Click To Generate ScreenShot</button>
<script>
function ScreenShot(){
 var element = document.getElementById('test');
html2canvas(element, {
    onrendered: function(canvas) {
//rendered canvas
        var download = document.createElement('a')//creating link for downloading image
      download.href =canvas.toDataURL();//use canvas.toDataURL('image/jpeg') for jpg file
 download.download = true;
download.text = 'Download';
 document.body.appendChild(download);

}
});
}
</script>
</body>