                        課程
                    
                        /前端開發(fā)
                        
                            /JavaScript
                        
                        /DOM事件探秘

如何解決鼠標(biāo)和鍵盤沖突的問題？

<!doctype?html>
<html>
<head>
????<meta?charset="UTF-8">
????<title>下拉菜單</title>
<style?type="text/css">
body,ul,li{?margin:0;?padding:0;?font-size:13px;}
ul,li{list-style:none;}
#divselect{width:186px;?margin:80px?auto;?position:relative;?z-index:10000;}
#divselect?cite{width:150px;?height:24px;line-height:24px;?display:block;?color:#807a62;?cursor:pointer;font-style:normal;
padding-left:4px;?padding-right:30px;?border:1px?solid?#333333;?
background:url(xjt.png)?no-repeat?right?center;}
#divselect?ul{width:184px;border:1px?solid?#333333;?background-color:#ffffff;?position:absolute;?z-index:20000;?margin-top:-1px;?display:none;}
#divselect?ul?li{height:24px;?line-height:24px;}
#divselect?ul?li?a{display:block;?height:24px;?color:#333333;?text-decoration:none;?padding-left:10px;?padding-right:10px;}
</style>
???<script?type="text/javascript">
window.onload=function(){
var?box=document.getElementById('divselect'),
???title=box.getElementsByTagName('cite')[0],
???menu=box.getElementsByTagName('ul')[0],
???as=box.getElementsByTagName('a'),
????????index=-1;
???
????//?點擊三角時
????title.onclick=function(event){
????????event=event||window.event;
????????menu.style.display='block'
????????if(event.stopPropagation){
????????event.stopPropagation();
??????}else{
??????????event.cancelBubble=true;
??????}
??????//?執(zhí)行腳本
??????document.onkeydown=function(event){
????????if?(event.keyCode==40)?{
??????????if?(index>=as.length)?{
????????????index=0;
??????????}else{
????????????index++;
??????????}
??????????for(var?i=0;i<as.length;i++){
??????????????as[i].style.background='#fff';
????????????}
???????????as[index].style.background='#ccc';
????????}
????????if?(event.keyCode==38){
??????????if?(index<=0)?{
????????????index=as.length-1;
??????????}else{
????????????index--;
??????????}
????????????for(var?i=0;i<as.length;i++){
??????????????as[i].style.background='#fff';
????????????}
???????????as[index].style.background='#ccc';
????????}
????????if(event.keyCode==13){
??????????if(index>=0&&index<=as.length){
????????????title.innerHTML=as[index].innerHTML;
????????????for(var?i=0;i<as.length;i++){
??????????????as[i].style.background='#fff';
????????????}
????????????index=-1;
????????????menu.style.display='none';
???????????}?
????????}
??????}
????}??
????
???//?滑過滑過、離開、點擊每個選項時
??????for(var?i=0;i<as.length;i++){
????????as[i].onmouseover=function(){
??????????this.style.background='#ccc';
????????}
????????as[i].onmouseout=function(){
??????????this.style.background='#fff';
????????}
????????as[i].onclick=function(event){
??????????title.innerHTML=this.innerHTML;
??????????event.stopPropagation();
??????????menu.style.display='none';
????????}
??????}
??????//?執(zhí)行腳本

???//?點擊頁面空白處時
???document.onclick=function(){
???????menu.style.display='none'
???}
???????//?執(zhí)行腳本
?}
???</script>
</head>
<body>
<div?id="divselect">
??????<cite>請選擇分類</cite>
??????<ul>
?????????<li?id="li"><a?href="javascript:;"?selectid="1">ASP開發(fā)</a></li>
?????????<li><a?href="javascript:;"?selectid="2">.NET開發(fā)</a></li>
?????????<li><a?href="javascript:;"?selectid="3">PHP開發(fā)</a></li>
?????????<li><a?href="javascript:;"?selectid="4">Javascript開發(fā)</a></li>
?????????<li><a?href="javascript:;"?selectid="5">Java特效</a></li>
??????</ul>
????</div>
</body>
</html>

先用鍵盤選擇一個，后用鼠標(biāo)劃過一個，如果兩個選得不一樣，會出現(xiàn)兩個選項，請問怎么解決？