问用touchmove事件替换mousemove

EN

var d=ctx.getImageData(0,0,canvas.width,canvas.height).data;
$hit=$("#hit");
$("#canvas").mousemove(function(e){handleMouseMove(e);});

tolerance = 20;
function handleMouseMove(e){

  e.preventDefault();
  e.stopPropagation();
  mouseX=parseInt(e.clientX-offsetX);
  mouseY=parseInt(e.clientY-offsetY);
  var isHit=d[(mouseY*cw+mouseX)*4+3]>tolerance;

  if(isHit){
    $hit.text("Yeahhhh");
  }else{
    //document.onmousemove = crash;
    $hit.text("Noooooooo");
  }
}