JS 伸缩效果代码 (上下伸缩)

        function toMinBox(obj) {
            var speed = 10;
            function strechH() {
                var h = obj.offsetHeight;
                if (h - speed <= 0) {
                    obj.style.display = "none";
                    clearInterval(intervalID_Min);
                }
                else {
                    obj.style.height = (h - speed) + "px";
                }
            }

            intervalID_Min = setInterval(strechH, 2);
        }

        function toMaxBox(obj) {
            obj.style.display = "block";
            var speed = 10;
            var originalHeight = !obj.childNodes[0].offsetHeight ? obj.getElementsByTagName("ul")[0].offsetHeight : obj.childNodes[0].offsetHeight;
            function strechM() {
                var h = obj.offsetHeight;
                if (h >= originalHeight) {
                    clearInterval(intervalID_Max);
                }
                else {
                    obj.style.height = (h + speed) + "px";
                }
            }

            intervalID_Max = setInterval(strechM, 2);
        }