Unable to get image data from canvas because the canvas has been tainted by cross-origin data.

此问题是因为用了Canvas GetImageData属性，兼容问题

此问题是在 IphoneXs机型 ios12 系统下复现
解决方案：
1. 抛出try catch
2. 将图片的地址加上时间戳，然后再设个跨域属性

var img = new Image();
var url = 'http:/wwww.baidu.com.jpg';
img.src = url + '?' + new Date().getTime();
img.setAttribute('crossOrigin', '');