网络图片转成base64

图片转成base64,通过线工具直接将图片拖进去就能得到base64编码。

现在用canvas的toDataURL()实现网络图片转base64：

 var imgurl = 'http://img0.imgtn.bdimg.com/it/u=1563847232,2166245740&fm=26&gp=0.jpg';
  imgBase(imgurl);
  function imgBase ( imgurl ){
        var img = new Image();
        img.setAttribute('crossOrigin','anonymous');//允许请求外域图片
        img.src = imgurl;
        img.onload = function(){
            var canvas = document.createElement('canvas');
            var ctx = canvas.getContext("2d");
            canvas.width = img.width;
            canvas.height = img.height;
            ctx.drawImage(img,0,0,img.width,img.height);
            var dataURL = canvas.toDataURL('image/jpg')
            console.log(dataURL);
        }
     }