关于javascript:JS实现下载图片JS实现把图片转成Base64

通过JavaScript脚本能够把近程的图片转换为Base64，通过JavaScript脚本能够把近程的图片下载到本地。

间接上代码：

//将近程图片转化为base64function getBase64(img){    function getBase64Image(img,width,height) {        //width、height调用时传入具体像素值，管制大小 ,不传则默认图像大小        var canvas = document.createElement("canvas");        canvas.width = width ? width : img.width;        canvas.height = height ? height : img.height;        var ctx = canvas.getContext("2d");        ctx.drawImage(img, 0, 0, canvas.width, canvas.height);        var dataURL = canvas.toDataURL();        return dataURL;    }    var image = new Image();    image.crossOrigin = '';    image.src = img;    return new Promise((resolve,reject)=>{        image.onload =function (){            resolve(getBase64Image(image));//将base64传给done上传解决        }    });}//把图片转换成base64getBase64('http://json.la/vx.jpg').then(base64 => {    console.log(base64)}, err => {    console.log(err)})//下载近程图片function downloadFile(url) {     var aLink = document.createElement('a');    var evt = document.createEvent("MouseEvents");    evt.initEvent("click", false, false);    aLink.download = url;    aLink.href = url;    aLink.dispatchEvent(evt);}downloadFile('http://json.la/vx.jpg')