Drop Down menu — onmouseout getting invoked on the child node when set in the parent node

问题

Trying to mimic the browse catagories in the following link https://dev.twitter.com/discussions

onmouseover -- the container expands to fit the new items within itself -- but,moving the mouse within the container(expanded conainer) will result in the onmouseout getting invoked -- even when the mouse is within the container itself -- silly mistake or not trying hard to find out where and how i might be going wrong

Code --

<html>
    <style type="text/css">
    #container{
    overflow: hidden;
    height: auto;
    width: 350px;
    background-color: rgba(0,0,0,0.65);
    }
    .contents{
    height: 30px;
    width: 350px;
    background-color: yellow;
    float: left;
    }
    </style>
    <script type="text/javascript" >
    var foo = new Array("bar","santa","claus")
    function fire(){
    var contents = document.getElementById("contents")
    if(contents.hasChildNodes())
    return
    for(i = 0 ; i < foo.length ; i++){
        var tem=document.createElement("div");
        tem.setAttribute("id",'cont'+i);
        tem.setAttribute("class","contents");
        tem.appendChild(document.createTextNode(foo[i]))
        contents.appendChild(tem)
    }
    }
    function unfire(evt){

    if ((evt.target || evt.srcElement).id != "container") 
    return;

    var contents = document.getElementById("contents");
    while(contents.hasChildNodes())
    contents.removeChild(contents.firstChild)
    }
    </script>

    <div id="container" onmouseover="fire(event)" onmouseout="unfire(event)">
        Move your mouse here
        <div id="contents" ></div>
    </div>
    </html>

回答1:

Sorry, I got my original answer completely wrong, I'm not sure what I was thinking. Of course, mouseout fires on a parent when the mouse moves to a child. In this case, you need to check the relatedTarget or toElement properties of the event object and check to see if that element is a descendant of the container.

You can check ancestry using contains() in Internet Explorer and compareDocumentPosition() in other browsers. For example, change onmouseout="unfire(event)" to onmouseout="unfire.call(this, event)" and add the following code to the unfire function:

var to = evt.relatedTarget || evt.toElement;

if((this.contains && this.contains(to)) || this.compareDocumentPosition(to) & 16)
    return;

来源：https://stackoverflow.com/questions/8850673/drop-down-menu-onmouseout-getting-invoked-on-the-child-node-when-set-in-the-p

标签

javascript

onmouseover

onmouseout