js HTML5 canvas绘制图片的方法

window.onload=function() {

  createcanvas();

  drawImage();

}

 function createcanvas() {

   var CANVAS=document.getElementById('mycanvas');

   context=CANVAS.getContext('2d');

 }

function drawImage() {

  var img=new Image();

  img.onload=function() {

    context.drawImage(img,0,0,200,200 );

  }

  img.src="img5.jpg";

}