function autoImg(img_select, img_url) {
                //img元素
                var img_element = $(img_select);
                //img路徑
                var img_url = img_url;
                //img父級元素的寬高比
                var parent_ratio = img_element.parent().width() / img_element.parent().height();

                var img = new Image();
                img.src = img_url;

                img.onload = function () {
                    var img_ratio = img.width / img.height;
                    // 判斷圖片相對與父元素寬小了還是高小了
                    if (img_ratio < parent_ratio) {
                        console.log("圖片寬小了");
                        img_element.css("width", "100%");
                    } else {
                        console.log("圖片高小了");
                        img_element.css("height", "100%");
                    }
                    img_element.attr("src", img_url);

                };
            };