// 对图片进行压缩 
    function compress(imgPath) {
    
        var image = new Image();
    
        //新建一个img标签（还没嵌入DOM节点) 
        image.src = imgPath;

        image.onload = function() {
    
            var canvas = document.createElement('canvas');
    
            var    context = canvas.getContext('2d');
    
            var    imageWidth = image.width / 3;
    
                //压缩后图片的大小 
            var    imageHeight = image.height / 3;
    
            var data = '';
    
            canvas.width = imageWidth;
     
            canvas.height = imageHeight;
    
            context.drawImage(image, 0, 0, imageWidth, imageHeight);
    
            data = canvas.toDataURL('image/jpeg')
            //压缩完成 
            $(".srcDiscernImg").attr("src", data);
    
            console.log("渲染。。。。");

        }

    }