discuz 门户页面支持导航顶部固定

<style type="text/css">
.floatnv{position:fixed;_position:absolute;top:0px;z-index:999;width:100%;}
</style>
<script language="javascript" type="text/javascript">
    (function() {
        var oDiv = document.getElementById("nv");
        var H = 0, iE6;
        var Y = oDiv;
        while (Y) {
            H += Y.offsetTop;
            Y = Y.offsetParent;
        };
        iE6 = window.ActiveXObject && !window.XMLHttpRequest;
        if (!iE6) {
            window.onscroll = function() {
                var s = document.body.scrollTop || document.documentElement.scrollTop;
                if (s > H) {
                    oDiv.className = "floatnv";
                    if (iE6) {
                        oDiv.style.top = (s - H) + "px";
                    }
                } else {
                    oDiv.className = "";
                }
            }
        }
    })();
</script>