canvas.toDataURL 由于跨域报错的解决方法

1、报错

Uncaught DOMException: Failed to execute 'toDataURL' on 'HTMLCanvasElement': Tainted canvases may not be exported.

2、解决

var img=new Image();
img.src="http://vsqx-cover-xxxxxx.coscd.myqcloud.com/"+this.vsqx_uid+".jpg";
//增加这一行，切记！！设置crossOrigin，一定要放在img.src后，否则个别安卓手机不生效
img.setAttribute("crossOrigin",'anonymous');