html5使用canvas实现图片下载功能的示例代码

<a href="图片src" download="下载海报">下载海报</a>

img.crossOrigin = 'anonymous';

canvas.toDataURL("image/png")

 var save_link = document.createElement('a');     save_link.href = image;     save_link.download ='测试.png';                            var clickevent = document.createEvent('MouseEvents');     clickevent.initEvent('click', true, false);     save_link.dispatchEvent(clickevent);

var canvas = $('.canvas');var cxt = canvas[0].getContext("2d");function save(){    var img = new Image();    img.crossOrigin = 'anonymous';    img.onload = function(){        var _w = img.naturalWidth;        var _h = img.naturalHeight;        canvas.attr({width:_w,height:_h});        cxt.drawImage(img,0,0);        var image = canvas[0].toDataURL("image/png")        var save_link = document.createElement('a');        save_link.href = image;        save_link.download ='测试.png';                                  var clickevent = document.createEvent('MouseEvents');           clickevent.initEvent('click', true, false);           save_link.dispatchEvent(clickevent);    };    img.src = 'http://n.sinaimg.cn/sports/transform/20170825/NZI3-    fykiufe6650492.jpg';}