<div?class="navbar?navbar-default">
??<div?class="navbar-header">
????<a?href="#"?class="navbar-brand">慕課網</a>
??</div>
??<ul?class="nav?navbar-nav">
????<li?class="active"><a?href="#">網站首頁</a></li>
????<li>
??????<a?href="#"?data-toggle="dropdown"?class="dropdown-toggle">
????????系列教程
????????<span?class="caret"></span>
??????</a>
??????<ul?class="dropdown-menu">
????????<li><a?href="#">CSS3</a></li>
????????<li><a?href="#">Javascript</a></li>
????????<li><a?href="#">PHP</a></li>
??????</ul>
????</li>
????<li><a?href="#">名師介紹</a></li>
????<li><a?href="#">成功案例</a></li>
????<li><a?href="#">關于我們</a></li>
??</ul>
??<form?action="#"?class="navbar-form?navbar-left"?role="search">
????<div?class="form-group">
??????<input?type="text"?class="form-control"?placeholder="請輸入關鍵詞"?/>
????</div>
????<button?type="submit"?class="btn?btn-default">搜索</button>
??</form>
</div>
<div?class="navbar?navbar-default"?role="navigation">
??　<div?class="navbar-header">
??　????<a?href="##"?class="navbar-brand">慕課網</a>
??　</div>
?????<ul?class="nav?navbar-nav">
????<li?class="active"><a?href="##">網站首頁</a></li>
??????<li?class="dropdown">
????????<a?href="##"?data-toggle="dropdown"?class="dropdown-toggle">系列教程<span?class="caret"></span></a>
????????<ul?class="dropdown-menu">
??????????<li><a?href="##">CSS3</a></li>
??????????<li><a?href="##">JavaScript</a></li>
??????????<li?class="disabled"><a?href="##">PHP</a></li>
????????</ul>
?????</li>
??????<li><a?href="##">名師介紹</a></li>
??????<li><a?href="##">成功案例</a></li>
??????<li><a?href="##">關于我們</a></li>
???</ul>
??<form?action="##"?class="navbar-form?navbar-left"?rol="search">
????<div?class="form-group">
??????<input?type="text"?class="form-control"?placeholder="請輸入關鍵詞"?/>
????</div>
?????<button?type="submit"?class="btn?btn-default">搜索</button>
???</form>
</div>

代碼一樣的，效果卻不一樣，后面是網站上的代碼