搜索框出现在下一排了，麻烦帮忙看看哪儿错了,谢谢！
<div class="nav clearfix"> <div class="nav_left"> </div> <div class="nav_middle"> <div class="nav_middle_left"> <ul> <li><a href="#">首页</a></li> <li><a href="">关于慕课</a></li> <li><a href="">新闻动态</a></li> <li><a href="">课程中心</a></li> <li><a href="">在线课程</a></li> <li><a href="">人才招聘</a></li> </ul> </div> <div class="nav_middle_right clearfix"> <form action="" method="post"> <input type="text" class="search_text"/> </form> </div> </div> <div class="nav_right"> </div> </div>
.nav{
height: 40px;
}
.nav_left{
width: 10px;
background: url(../images/nav_left.jpg) no-repeat;
float: left;
height: 40px;
}
.nav_middle{
width: 980px;
background: url(../images/nav_bg.jpg) repeat-x;
float: left;
}
.nav_right{
width: 10px;
background: url(../images/nav_right.jpg) no-repeat;
float: right;
height: 40px;
}
.nav_middle_left{
width: 680px;
}
.nav_middle_right{
width: 300px;
}
.nav_middle_left li{
float: left;
list-style-type: none;
width: 100px;
text-align: center;
line-height: 40px;
}
.nav_middle_left li:after{
clear: both;
}
.nav_middle_left a:link,.nav_middle_left a:visited{
text-decoration: none;
color: #FFF;
font-size: 16px;
font-family: "微软雅黑";
}
.nav_middle_left a:hover,.nav_middle_left a:active{
text-decoration: none;
color: #FF0;
font-size: 16px;
font-family: "微软雅黑";
}
.search_text{
width: 190px;
height: 25px;
margin-top: 5px;
float: left;
}
我检查过nav_middle宽度为980px，nav_middle_left为680px,nav_middle_right为300px;
其中的搜索框才190px,然后又将.nav_middle_left li:after{clear:both;}了一下，还是没有改变。。。
