function drawcircle(id,x,y,r){
var ca = document.getElementById(id);
var cans = ca.getContext("2d");
cans.globalCompositeOperation = "destination-out";
cans.beginPath();
cans.arc(x,y,r,0,Math.PI*2);
//解决兼容
ca.style.display = ‘none’;
ca.offsetHeight;
ca.style.display = ‘inherit’;
//解决兼容
cans.fillStyle="#000";
cans.fill();
}
这样可以解决
参考自:http://bbs.csdn.net/topics/390808206
解决在android里面(三星s3)等一些4.1系统的手机上cancas刮刮乐无效
原文:http://my.oschina.net/u/2255569/blog/359234