怎么解决按下回车键，才选择该选项？
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>下拉菜单</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("images/xiala-.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;}
#divselect ul li a:hover{
background: #567;
}
</style>
<script type="text/javascript">
var eventUtil ={
//添加句柄
addHander:function (ele,type,handler) {
if(ele.addEventListener){
ele.addEventListener(type,handler,false);
}else if(ele.attachEvent){
ele.attachEvent('on'+type,handler);
}else {
ele['on'+type] =handler;
}
},
//获取事件类型
getEvent:function (event) {
return event?event:window.event;
},
//阻止事件默认行为
preventDefault:function (event) {
if(event.preventDefault){
event.preventDefault();
}else{
event.returnValue = false;
}
},
//阻止事件冒泡
stopPropagation:function (event) {
if(event.stopPropagation){
event.stopPropagation();
}else{
event.cancelBubble = true;
}
}
}
window.onload=function() {
var box = document.getElementById('divselect'),
title = box.getElementsByTagName('cite')[0],
menu = box.getElementsByTagName('ul')[0],
as = box.getElementsByTagName('a'),
index = -1,
flag = 0;
for (var i = 0; i < as.length; i++) {
eventUtil.addHander(as[i], 'click', function (event) {
//获取事件类型
eventUtil.getEvent(event);
//阻止事件默认行为
eventUtil.preventDefault(event);
//阻止事件冒泡
eventUtil.stopPropagation(event);
title.innerHTML = this.innerHTML;
menu.style.display = 'none';
return false;
})
}
// 点击三角时
eventUtil.addHander(title, 'click', function (event) {
//获取事件类型
eventUtil.getEvent(event);
//阻止事件默认行为
eventUtil.preventDefault(event);
//阻止事件冒泡
eventUtil.stopPropagation(event);
var menu = box.getElementsByTagName('ul')[0];
if (menu.style.display == "block") {
menu.style.display = "none";
} else {
menu.style.display = "block"
}
})
//操作键盘触发相应事件
document.onkeyup = function (event) {
//获取事件类型
eventUtil.getEvent(event);
//阻止事件默认行为
eventUtil.preventDefault(event);
//阻止事件冒泡
eventUtil.stopPropagation(event);
//按回车键显示或隐藏
if(event.keyCode==13){
if(flag==0){
menu.style.display = 'block';
flag=1;
return false;
}else{
menu.style.display = 'none';
flag = 0;
return false;
}
}
if(menu.style.display == 'block'){
//向下
if (event.keyCode == 40) {
index++;
if (index >= as.length) index = 0;
for (var j = 0; j < as.length; j++) {
as[j].style.background = '#fff';
}
as[index].style.background = '#567';
title.innerHTML = as[index].innerHTML;
}
//向上
if (event.keyCode == 38) {
index--;
if (index < 0) index = as.length - 1;
for (var k = 0; k < as.length; k++) {
as[k].style.background = '#fff';
}
as[index].style.background = '#567';
title.innerHTML = as[index].innerHTML;
}
}
// 点击页面空白处时
eventUtil.addHander(document, 'click', function (event) {
//获取事件类型
eventUtil.getEvent(event);
//阻止事件默认行为
eventUtil.preventDefault(event);
//阻止事件冒泡
eventUtil.stopPropagation(event);
})
}
}
</script>
</head>
<body>
<div id="divselect">
<cite>请选择分类</cite>
<ul>
<li id="li"><a href="javascript:;" selectid="1">ASP开发</a></li>
<li><a href="javascript:;" selectid="2">.NET开发</a></li>
<li><a href="javascript:;" selectid="3">PHP开发</a></li>
<li><a href="javascript:;" selectid="4">Javascript开发</a></li>
<li><a href="javascript:;" selectid="5">Java特效</a></li>
</ul>
</div>
</body>
</html>
