固定菜單 · 前端开发

``` <!DOCTYPE HTML> <html> <head> <meta charset="UTF-8"> <title>固定菜單</title> </head> <body> <style type="text/css"> .wrapper { height: 2000px; } #fix_menu_bar { top: 0; } </style> <div class="wrapper"> <div id="fix_menu_bar"> <a href="http://keleyi.com/menu/net/" target="_blank">.NET</a> </div> </div> <script type="text/javascript"> function menuFixed(id) { var obj = document.getElementById(id); var _getHeight = obj.offsetTop; window.onscroll = function() { changePos(id, _getHeight); } } function changePos(id, height) { var obj = document.getElementById(id); var scrollTop = document.documentElement.scrollTop || document.body.scrollTop; if(scrollTop < height) { obj.style.position = 'relative'; } else { obj.style.position = 'fixed'; } } </script> <script type="text/javascript"> window.onload = function() { menuFixed('fix_menu_bar'); } </script> </body> </html> ```