为什么没有菜单的背景颜色改变？(Why doesn't the menu backgroun

我创建了2 menus:prod & prod2 ，我发现当mouse focus on prod2 ，背景颜色改变，但是当鼠标焦点prod1 the background color doesn't change 。

为什么不能改变？

样式：

ul.hMenu  { 
    margin: 0;
    padding: 0; 
    z-index: 1;                 
}
ul.hMenu > li  {  
    margin: 0;
    padding: 0;
    list-style: none;
    float: left;
    width:140px;
}
ul.hMenu li a { 
    display: block; 
    text-align: left;
    text-decoration: none
}          
ul.hMenu li > div  {                    
    position: absolute;             
    display: none;                
}
ul.hMenu div a {background: yellow;     
}           

div.lay1{ float:left;}  
div.lay1 br{line-height:50%}
.topMenu{font:bold 12px arial;color:#169e39;text-decoration: none;}
.secondMenu{font:12px arial;color:#000000;text-decoration: none;}
.arrow_box {
    position: relative;
    background: red;
    border: 4px solid #c2e1f5;
}
.arrow_box:after, .arrow_box:before {
    bottom: 100%;
    border: solid transparent;
    content: " ";
    height: 0;
    width: 0;
    position: absolute;
    pointer-events: none;
}
.arrow_box:after {
    border-color: rgba(149, 213, 53, 0);
    border-bottom-color: red;
    border-width: 13px;
    left: 10%;
    margin-left: -13px;
}
.arrow_box:before {
    border-color: rgba(194, 225, 245, 0);
    border-bottom-color: #c2e1f5;
    border-width: 19px;
    left: 10%;
    margin-left: -19px;
}

脚本：

function showMenu(obj){             
    var a=obj.children[0];
    a.style.color="blue";
    var div = obj.children[1];
    obj.style.backgroundColor="yellow";


    div.style.display="block";  

}
function hideMenu(obj){
    var a=obj.children[0];
    a.style.color="red";
    var div = obj.children[1];          
    div.style.display="none";
    obj.style.backgroundColor="";
}

HTML：

<ul class="hMenu">          
    <li  onmouseover="showMenu(this);" onmouseout="hideMenu(this);">
        <a style="color: red;" href="javascript:void(0);">prod</a>              
        <div><br/> 
            <!-- here-->
            <div class="arrow_box" >  
                <div class="lay1">
                   <div><a href=""  class="topMenu">Manage Content</a><br><a href=""  class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;Message </a></div>
                   <br><br>
                   <div><a href=""  class="topMenu">Manage Assignment</a><br><a href=""  class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;User Inquiry</a></div>
                </div>
            </div>
        </div>
    </li>     
    <li onmouseover="showMenu(this);" onmouseout="hideMenu(this);">
        <a style="color: red;" href="javascript:void(0);">prod2</a>
        <div  class="arrow_box">                                               
            <div  class="lay1">
                <div><a href=""  class="topMenu">Manage Content</a><br><a href=""  class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;Message </a><br><a href=""  class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;Help </a></div>
                <br><br>
                <div><a href=""  class="topMenu">Manage Assignment</a><br><a href=""  class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;User Inquiry</a></div>
            </div>
        </div>
    </li>  
</ul>   
<br/><br/><br/><br/><br/>
Test

问题在的jsfiddle

Answer 1:

我测试你的代码，它的工作！你是什么浏览器？请将演示，也可以添加该代码以及

a.setAttribute('style','background-color:blue');

一些浏览器有不兼容element.style

Answer 2:

给CSS像这样

.arrow_box{ position:absolute; white-space:nowrap}

勾选此

http://jsfiddle.net/zz5XJ/2/

Answer 3:

试试下面的HTML：

            <body>          
                <ul class="hMenu">          
                    <li  onmouseover="showMenu(this);" onmouseout="hideMenu(this);">
                        <a style="color: red;" href="javascript:void(0);">prod</a>              
                             <div class="arrow_box" >  
                                <div class="lay1">
                                   <div><a href=""  class="topMenu">Manage Content</a><br><a href=""  class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;Message </a></div>
                                   <br><br>
                                   <div><a href=""  class="topMenu">Manage Assignment</a><br><a href=""  class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;User Inquiry</a></div>
                                </div>
                            </div>

                    </li>     
                    <li onmouseover="showMenu(this);" onmouseout="hideMenu(this);">
                        <a style="color: red;" href="javascript:void(0);">prod2</a>
                        <div  class="arrow_box">                                               
                            <div  class="lay1">
                                <div><a href=""  class="topMenu">Manage Content</a><br><a href=""  class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;Message </a><br><a href=""  class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;Help </a></div>
                                <br><br>
                                <div><a href=""  class="topMenu">Manage Assignment</a><br><a href=""  class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;User Inquiry</a></div>
                            </div>
                        </div>
                    </li>  
                </ul>   
                <br/><br/><br/><br/><br/>
                Test
            </body>

Answer 4:

请检查您的HTML：

因为你们两个执行相同功能Pord or Pord2但内部HTML是两种不同的li 。所以function showMenu()同时适用于不同Pord or Pord2 ：

HTML：

<ul class="hMenu">
        <li onmouseover="showMenu(this);" onmouseout="hideMenu(this);"><a style="color: red;"
            href="javascript:void(0);">prod</a>           
            <div class="arrow_box">
             <br />
                <div class="lay1">
                    <div>
                        <a href="" class="topMenu">Manage Content</a><br>
                        <a href="" class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;Message </a>
                    </div>
                    <br />
                    <br />
                    <div>
                        <a href="" class="topMenu">Manage Assignment</a><br>
                        <a href="" class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;User Inquiry</a></div>
                </div>
            </div>
        </li>
        <li onmouseover="showMenu(this);" onmouseout="hideMenu(this);"><a style="color: red;"
            href="javascript:void(0);">prod2</a>            
            <div class="arrow_box">
            <br />
                <div class="lay1">
                    <div>
                        <a href="" class="topMenu">Manage Content</a><br>
                        <a href="" class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;Message </a>
                        <br>
                        <a href="" class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;Help </a>
                    </div>
                    <br />
                    <br />
                    <div>
                        <a href="" class="topMenu">Manage Assignment</a><br>
                        <a href="" class="secondMenu">&nbsp;&nbsp;&nbsp;&nbsp;User Inquiry</a></div>
                </div>
            </div>
        </li>
    </ul>

尝试这个

更新

把<br />之前arrow_box DIV两种li和一些零钱为JavaScript：

var div = obj.children[2];

使用Javascript -

   function showMenu(obj){ 
                var a=obj.children[0];
                a.style.color="blue";
                var div = obj.children[2];
                obj.style.backgroundColor="yellow";
                div.style.display="block";
            }

    function hideMenu(obj){
                var a=obj.children[0];
                a.style.color="red";
                var div = obj.children[2];          
                div.style.display="none";
                obj.style.backgroundColor="";
            }

更新的jsfiddle

文章来源: Why doesn't the menu background color change?