摘要：
js部份：function toolbar(el) { el = typeof el == 'string' ? document.getElementById(el) : el; var elTop = el.offsetTop; var sTop = 0; window.onscroll = function () { sTop = document.body.scrollTop || document.documentElement.scrollTop; if (sTop > elTop) { el.style.top = "0"; el.sty 阅读全文
