html 2 canvas screen shots [not working]

using this to convert the demo div into a canvas element which can be saved http://html2canvas.hertzen.com/ http://www.kubilayerdogan.net/html2canvas-take-screenshot-of-web-page-and-save-it-to-server-javascript-and-php/ //save.php code //Show the image echo ''; //Get the base-64 string from data $filteredData=substr($_POST['img_val'], strpos($_POST['img_val'], ",")+1); //Decode the string $unencodedData=base64_decode($filteredData); //Save the image file_put_contents('img.png', $unencodedData);