js将图片转成Base64编码格式

   // 图片文件转base64，利用canvas
    function getBase64Image(img) {
        var canvas = document.createElement("canvas");
        canvas.width = img.width;
        canvas.height = img.height;
        var ctx = canvas.getContext("2d");
        ctx.drawImage(img, 0, 0, img.width, img.height);
        var ext = img.src.substring(img.src.lastIndexOf(".")+1).toLowerCase();
        var dataURL = canvas.toDataURL("image/"+ext);
        return dataURL;
    }


    // 使用
    var image = new Image();
    image.src = "${ctxStatic}/modules/cms/front/site/suzhou/img/login-bg.jpg";  //你的图片路径
    image.onload = function(){
        var imgBase64 = getBase64Image(image);
        console.log(imgBase64);
    }

测试结果如图所示：

具体详情可以参考以下博客
https://www.youkuaiyun.com/tags/Ntjacg5sODkwMzMtYmxvZwO0O0OO0O0O.html