A canvas createPattern example

function boot() {
  draw(document.getElementById('canvas').getContext('2d'));
  draw(document.getElementById('vmlcanvas').getContext('2d'));
}
function draw(ctx) {
  // create new image object to use as pattern
  var img = new Image();
  img.onload = function(){
    // create pattern
    var ptrn = ctx.createPattern(img,'repeat');
    ctx.fillStyle = ptrn;
    ctx.fillRect(0,0,150,150);
  }
  img.src = 'images/wallpaper.png?' + new Date().getTime();
}