// 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。。。。");

        }

    }