本文實例講述了JavaScript實現鼠標點擊後層展開效果的方法。分享給大家供大家參考。具體分析如下：
這段JavaScript代碼可實現鼠標點擊後層展開的功能，代碼稍嫌復雜，重在學習研究，有興趣的可以修改簡化一下。
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>層展開折疊</title>
</head>
<body>
<style type="text/css">
DIV.clTopMenu{
position:absolute;
width:101;
height:150;
clip:rect(0,101,14,0);
visibility:hidden;
z-index:31;
layer-background-color:#EEEEEE;
background-color:#00CCFF
}
DIV.clTopMenuBottom{
position:absolute;
width:101;
height:3;
clip:rect(0,101,3,0);
top:11;
layer-background-color:#CECFCE;
background-color:#000099;
z-index:2
}
DIV.clTopMenuText{
position:absolute;
width:91;
left:5;
top:15;
font-family:"Arial", "Helvetica", "sans-serif";
font-size:9pt;
background-color:#EEEEEE;
z-index:1;
color: #000000
}
a:link {
color: #000000;
text-decoration: none
}
</style>
<script language="JavaScript" type="text/javascript">
function lib_bwcheck(){ //Browsercheck (needed)
this.ver=navigator.appVersion
this.agent=navigator.userAgent
this.dom=document.getElementById?1:0
this.opera5=this.agent.indexOf("Opera 5")>-1
this.ie5=(this.ver.indexOf("MSIE 5")>-1 && this.dom && !this.opera5)?1:0;
this.ie6=(this.ver.indexOf("MSIE 6")>-1 && this.dom && !this.opera5)?1:0;
this.ie4=(document.all && !this.dom && !this.opera5)?1:0;
this.ie=this.ie4||this.ie5||this.ie6
this.mac=this.agent.indexOf("Mac")>-1
this.ns6=(this.dom && parseInt(this.ver) >= 5) ?1:0;
this.ns4=(document.layers && !this.dom)?1:0;
this.bw=(this.ie6 || this.ie5 || this.ie4 || this.ns4 || this.ns6 || this.opera5)
return this
}
var bw=new lib_bwcheck()
nPlace=0
var nNumberOfMenus=2
var nMwidth=101
var nPxbetween=20
var nFromleft=10
var nFromtop=20
var nBgcolor='#CECFCE'
var nBgcolorchangeto='#6380BC'
var nImageheight=11
function makeNewsMenu(obj,nest){
nest=(!nest) ? "":'document.'+nest+'.'
this.css=bw.dom? document.getElementById(obj).style:bw.ie4?document.all[obj].style:bw.ns4?eval(nest+"document.layers." +obj):0;
this.evnt=bw.dom? document.getElementById(obj):bw.ie4?document.all[obj]:bw.ns4?eval(nest+"document.layers." +obj):0;
this.scrollHeight=bw.ns4?this.css.document.height:this.evnt.offsetHeight
this.moveIt=b_moveIt;this.bgChange=b_bgChange;
this.slideUp=b_slideUp; this.slideDown=b_slideDown;
this.clipTo=b_clipTo;
this.obj = obj + "Object"; eval(this.obj + "=this")
}
function b_moveIt(x,y){this.x=x; this.y=y; this.css.left=this.x; this.css.top=this.y}
function b_bgChange(color){if(bw.dom || bw.ie4) this.css.backgroundColor=color; else this.css.bgColor=color}
function b_clipTo(t,r,b,l){
if(bw.ns4){this.css.clip.top=t; this.css.clip.right=r; this.css.clip.bottom=b; this.css.clip.left=l
}else this.css.clip="rect("+t+","+r+","+b+","+l+")";
}
function b_slideUp(ystop,moveby,speed,fn,wh){
if(!this.slideactive){
if(this.y>ystop){
this.moveIt(this.x,this.y-5); eval(wh)
setTimeout(this.obj+".slideUp("+ystop+","+moveby+","+speed+",'"+fn+"','"+wh+"')",speed)
}else{
this.slideactive=false; this.moveIt(0,ystop); eval(fn)
}
}
}
function b_slideDown(ystop,moveby,speed,fn,wh){
if(!this.slideactive){
if(this.y<ystop){
this.moveIt(this.x,this.y+5); eval(wh)
setTimeout(this.obj+".slideDown("+ystop+","+moveby+","+speed+",'"+fn+"','"+wh+"')",speed)
}else{
this.slideactive=false; this.moveIt(0,ystop); eval(fn)
}
}
}
function newsMenuInit(){
oTopMenu=new Array()
zindex=10
for(i=0;i<=nNumberOfMenus;i++){
oTopMenu[i]=new Array()
oTopMenu[i][0]=new makeNewsMenu('divTopMenu'+i)
oTopMenu[i][1]=new makeNewsMenu('divTopMenuBottom'+i,'divTopMenu'+i)
oTopMenu[i][2]=new makeNewsMenu('divTopMenuText'+i,'divTopMenu'+i)
oTopMenu[i][1].moveIt(0,nImageheight)
oTopMenu[i][0].clipTo(0,nMwidth,nImageheight+3,0)
if(!nPlace) oTopMenu[i][0].moveIt(i*nMwidth+nFromleft+(i*nPxbetween),nFromtop)
else{
oTopMenu[i][0].moveIt(nFromleft,i*nImageheight+nFromtop+(i*nPxbetween))
oTopMenu[i][0].css.zIndex=zindex--
}
oTopMenu[i][0].css.visibility="visible"
}
}
function topMenu(num){
if(oTopMenu[num][1].y==nImageheight) oTopMenu[num][1].slideDown(oTopMenu[num][2].scrollHeight+20,10,40,'oTopMenu['+num+'][0].clipTo(0,nMwidth,oTopMenu['+num+'][1].y+3,0)','oTopMenu['+num+'][0].clipTo(0,nMwidth,oTopMenu['+num+'][1].y+3,0)')
else if(oTopMenu[num][1].y==oTopMenu[num][2].scrollHeight+20) oTopMenu[num][1].slideUp(nImageheight,10,40,'oTopMenu['+num+'][0].clipTo(0,nMwidth,oTopMenu['+num+'][1].y+3,0)','oTopMenu['+num+'][0].clipTo(0,nMwidth,oTopMenu['+num+'][1].y+3,0)')
}
function menuOver(num){oTopMenu[num][1].bgChange(nBgcolorchangeto)}
function menuOut(num){oTopMenu[num][1].bgChange(nBgcolor)}
onload=newsMenuInit;
</script>
<div id="divTopMenu0" class="clTopMenu" align="center" style="height: 170; left: 20; top: 20"><span class="css3"><a href="#" onMouseOver="menuOver(0)" onMouseOut="menuOut(0)" onClick="topMenu(0); if(bw.dom || bw.ie4)this.blur(); return false">點擊展開</a>
</span>
<div id="divTopMenuText0" class="clTopMenuText">
<span class="css3">
鼠標點擊後層展開JavaScript鼠標點擊後層展開JavaScript。
</span>
</div>
<div id="divTopMenuBottom0" class="clTopMenuBottom" style="top: 11; height: 10"></div>
</div>
</div>
</body>
</html>
希望本文所述對大家的javascript程序設計有所幫助。