use this code to save image from canvas
function save_canvas_img()
{
var canvas = document.getElementById("your id");
var canvasData = canvas.toDataURL("image/png");
var ajax = new XMLHttpRequest();
ajax.open("POST",'save.php',false);
ajax.setRequestHeader('Content-Type', 'application/your page name');
ajax.send(canvasData );
alert('You have successfully saved this image');
}`enter code here`
here save.php
if (isset($GLOBALS["HTTP_RAW_POST_DATA"]))
{
$imageData=$GLOBALS['HTTP_RAW_POST_DATA'];
$filteredData=substr($imageData, strpos($imageData, ",")+1);
$unencodedData=base64_decode($filteredData);
// Need to decode before saving since the data we received is already base64 encoded
//echo "unencodedData".$unencodedData;
$randomName = mktime(). rand(99999,9999999). '.png';
$fp = fopen( 'foldername/'.$randomName, 'wb' );
fwrite( $fp, $unencodedData);
fclose( $fp );}`enter code here`