CSS+DIV下拉菜单
这是JS文件
//Chrome Drop Down Menu- Author: Dynamic Drive (http://www.dynamicdrive.com)
//Last updated: June 14th, 06 '
var cssdropdown={
disappeardelay: 250, //set delay in miliseconds before menu disappears onmouseout
disablemenuclick: true, //when user clicks on a menu item with a drop down menu, disable menu item 's link?
enableswipe: 1, //enable swipe effect? 1 for yes, 0 for no
//No need to edit beyond here////////////////////////
dropmenuobj: null, ie: document.all, firefox: document.getElementById&&!document.all, swipetimer: undefined, bottomclip:0,
getposOffset:function(what, offsettype){
var totaloffset=(offsettype== "left ")? what.offsetLeft : what.offsetTop;
var parentEl=what.offsetParent;
while (parentEl!=null){
totaloffset=(offsettype== "left ")? totaloffset+parentEl.offsetLeft : totaloffset+parentEl.offsetTop;
parentEl=parentEl.offsetParent;
}
return totaloffset;
},
swipeeffect:function(){
if (this.bottomclip <parseInt(this.dropmenuobj.offsetHeight)){
this.bottomclip+=10+(this.bottomclip/10) //unclip drop down menu visibility gradually
this.dropmenuobj.style.clip= "rect(0 auto "+this.bottomclip+ "px 0) "
}
else
return
this.swipetimer=setTimeout( "cssdropdown.swipeeffect() ", 10)
},
showhide:function(obj, e){
if (this.ie || this.firefox)
this.dropmenuobj.style.left=this.dropmenuobj.style.top= "-500px "
if (e.type== "click " && obj.visibility==hidden || e.type== "mouseover "){
if (this.enableswipe==1){
if (typeof this.swipetimer!= "undefined ")
clearTimeout(this.swipetimer)
obj.clip= "rect(0 auto 0 0) " //hide menu via clipping
this.bottomclip=0
this.swipeeffect()
}
obj.visibility= "visible "
}
else if (e.type== "click ")
obj.visibility= "hidden "
},
iecompattest:function(){
return (document.compatMode && document.compatMode!= "BackCompat ")? document.documentElement : document.body
},
clearbrowseredge:function(obj, whichedge){
var edgeoffset=0
if (whichedge== "rightedge "){
var windowedge=this.ie && !window.opera? this.iecompattest().scrollLeft+this.iecompattest().clientWidth-15 : window.pageXOffset+window.innerWidth-15
this.dropmenuobj.contentmeasure=this.dropmenuobj.offsetWidth
if (windowedge-this.dropmenuobj.x < this.dropmenuobj.contentmeasure) //move menu to the left?
edgeoffset=this.dropmenuobj.contentmeasure-obj.offsetWidth
}
else{
var topedge=this.ie && !window.opera? this.iecompattest().scrollTop : window.pageYOffset
var windowedge=this.ie && !window.opera? this.iecompattest().scrollTop+this.iecompattest().clientHeight-15 : window.pageYOffset+window.innerHeight-18
this.dropmenuobj.contentmeasure=this.dropmenuobj.offsetHeight
if (windowedge-this.dropmenuobj.y < this.dropmenuobj.contentmeasure){ //move up?
edgeoffset=this.dropmenuobj.contentmeasure+obj.offsetHeight
if ((this.dropmenuobj.y-topedge) <this.dropmenuobj.contentmeasure) //up no good either?
edgeoffset=this.dropmenuobj.y+obj.offsetHeight-topedge
}
}
return edgeoffset
},
dropit:function(obj, e, dropmenuID){
if (this.dropmenuobj!=null) //hide previous menu
this.dropmenuobj.style.visibility= "hidden " //hide menu
this.clearhidemenu()
if (this.ie||this.firefox){
obj.onmouseout=function(){cssdropdown.delayhidemenu()}
obj.onclick=function(){return !cssdropdown.disablemenuclick} //disable main menu item link onclick?
this.dropmenuobj=document.getElementById(dropmenuID)
this.dropmenuobj.onmouseover=function(){cssdropdown.clearhidemenu()}
this.dropmenuobj.onmouseout=function(){cssdropdown.dynamichide(e)}
this.dropmenuobj.onclick=function(){cssdropdown.delayhidemenu()}
this.showhide(this.dropmenuobj.style, e)
this.dropmenuobj.x=this.getposOffset(obj, "left ")
this.dropmenuobj.y=this.getposOffset(obj, "top ")
this.dropmenuobj.style.left=this.dropmenuobj.x-this.clearbrowseredge(obj, "rightedge ")+ "px "
this.dropmenuobj.style.top=this.dropmenuobj.y-this.clearbrowseredge(obj, "bottomedge ")+obj.offsetHeight+1+ "px "
}
},
contains_firefox:function(a, b) {
while (b.parentNode)
if ((b = b.parentNode) == a)
return true;
return false;
},
dynamichide:function(e){
var evtobj=window.event? window.event : e
if (this.ie&&!this.dropmenuobj.contains(evtobj.toElement))
this.delayhidemenu()
else if (this.firefox&&e.currentTarget!= evtobj.relatedTarget&& !this.contains_firefox(evtobj.currentTarget, evtobj.relatedTarget))
this.delayhidemenu()
},
delayhidemenu:function(){
this.delayhide=setTimeout( "cssdropdown.dropmenuobj.style.visibility= 'hidden ' ",this.disappeardelay) //hide menu
},
clearhidemenu:function(){
if (this.delayhide!= "undefined ")
clearTimeout(this.delayhide)
},
startchrome:function(){
for (var ids=0; ids <arguments.length; ids++){
var menuitems=document.getElementById(arguments[ids]).getElementsByTagName( "a ")
for (var i=0; i <menuitems.length; i++){
if (menuitems[i].getAttribute( "rel ")){
var relvalue=menuitems[i].getAttribute( "rel ")
menuitems[i].onmouseover=function(e){
var event=typeof e!= "undefined "? e : window.event
cssdropdown.dropit(this,event,this.getAttribute( "rel "))
}
}
}
}
}
}
[解决办法]
javascript跨浏览器兼容性问题
开发者的噩梦!
