跟著視頻敲的，這里就是對(duì)不齊，怎么回事？用360瀏覽器，IE都一樣。.nav{ height:40px; }.nav_left{ width:10px; background:url(../images/nav_left.jpg) no-repeat; float:left; height:40px; }.nav_right{ width:10px; background:url(../images/nav_right.jpg) no-repeat; float:left; height:40px; }.nav_mid{ width:980px; background:url(../images/nav_bg.jpg) repeat-x; float:left; }