Frame by frame animation in HTML5 with canvas

To create a frame by frame animation in HTML5 with canvas, try to run the following code:

var myImageNum = 1; var lastImage = 5; var context = canvas.getContext('2d'); var img = new Image; img.onload = function(){    context.clearRect( 0, 0, context.canvas.width, context.canvas.height );    context.drawImage( img, 0, 0 ); }; var timer = setInterval( function(){    if (myImageNum > lastImage){       clearInterval( timer );    }else{       img.src = "images/left_hnd_"+( myImageNum++ )+".png";    } }, 1000/15 );