​x
 
<!DOCTYPE html>
<html>
<body>
​
<canvas id="myCanvas" width="300" height="150" style="border:1px solid #d3d3d3;">
Your browser does not support the HTML5 canvas tag.
</canvas>
​
<script>
​
var c=document.getElementById("myCanvas");
var ctx=c.getContext("2d");
var imgData=ctx.createImageData(100,100);
alert("Width of imgData is: " + imgData.width);
for (var i=0;i<imgData.data.length;i+=4)
  {
  imgData.data[i+0]=255;
  imgData.data[i+1]=0;
  imgData.data[i+2]=0;
  imgData.data[i+3]=255;
  }
ctx.putImageData(imgData,10,10);
​
</script>
​
</body>
</html>
​