新浪微博“大家正在说”文字上下滚动渐隐效果

Question

<script language="javascript" type="text/javascript">
        var b = window.b || {};

        b.roll = function () {
            var me =  this;
            setTimeout(function () {
                me.x = document.getElementsByTagName("ul");
                me.y = document.getElementsByTagName("li");
                me.z = me.y.item(me.y.length - 1);
                me.q = me.z.clientHeight;
                me.z.style.opacity = 0;
                me.z.style.filter = "alpha:(opacity=0)";
                me.z.style.filter = "progid:DXImageTransform.Microsoft.Alpha(opacity=" + 0 + ")";
                me.z.style.height = "0px";
                me.x[0].insertBefore(me.z, me.y[0]);
                me.t = 1;
                me.c = 0
                me.i = setInterval(function () {
                    me.t++;
                    me.z.style.height = Math.round(me.q * (me.t / 50) * (me.t / 50)) + "px";
                    if (me.t >= 50) {
                        clearInterval(me.i);
                        me.d = setInterval(function () {
                            me.c += 0.02
                            if ("\v" == "v") {
                                me.z.style.filter = "alpha:(opacity=" + me.c * 100 + ")";
                                me.z.style.filter = "progid:DXImageTransform.Microsoft.Alpha(opacity=" + me.c * 100 + ")";
                            }
                            me.z.style.opacity = me.c;
                            if (me.c >= 1) { clearInterval(me.d); }
                        }, 50)
                    }
                }, 25)
                b.roll();
            }, 5000);
        }
        new b.roll();
</script>

有哪位高手能解释一下这段代码？

Answer 1

这段代码并不复杂，没有特别难懂的知识点，最难懂的估计就是变量名太短容易混淆吧。 不过这段代码有缺陷倒是真的，里面很多不该重复定义的变量都在每次的setTimeout中重复了，浪费

Answer 2

收藏学习