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From 2013.igem.org

//** Chrome Drop Down Menu- Author: Dynamic Drive (http://www.dynamicdrive.com)

//** Updated: July 14th 06' to v2.0 //1) Ability to "left", "center", or "right" align the menu items easily, just by modifying the CSS property "text-align". //2) Added an optional "swipe down" transitional effect for revealing the drop down menus. //3) Support for multiple Chrome menus on the same page.

//** Updated: Nov 14th 06' to v2.01- added iframe shim technique

//** Updated: July 23rd, 08 to v2.4 //1) Main menu items now remain "selected" (CSS class "selected" applied) when user moves mouse into corresponding drop down menu. //2) Adds ability to specify arbitrary HTML that gets added to the end of each menu item that carries a drop down menu (ie: a down arrow image). //3) All event handlers added to the menu are now unobstrusive, allowing you to define your own "onmouseover" or "onclick" events on the menu items. //4) Fixed elusive JS error in FF that sometimes occurs when mouse quickly moves between main menu items and drop down menus

//** Updated: Oct 29th, 08 to v2.5 (only .js file modified from v2.4) //1) Added ability to customize reveal animation speed (# of steps) //2) Menu now works in IE8 beta2 (a valid doctype at the top of the page is required)

var cssdropdown={ disappeardelay: 250, //set delay in miliseconds before menu disappears onmouseout

//specify full HTML to add to end of each menu item with a drop down menu

enablereveal: [true, 5], //enable swipe effect? [true/false, steps (Number of animation steps. Integer between 1-20. Smaller=faster)] enableiframeshim: 1, //enable "iframe shim" in IE5.5 to IE7? (1=yes, 0=no)

//No need to edit beyond here////////////////////////

dropmenuobj: null, asscmenuitem: null, domsupport: document.all || document.getElementById, standardbody: null, iframeshimadded: false, revealtimers: {},

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; },

css:function(el, targetclass, action){ var needle=new RegExp("(^|\\s+)"+targetclass+"($|\\s+)", "ig") if (action=="check") return needle.test(el.className) else if (action=="remove") el.className=el.className.replace(needle, "") else if (action=="add" && !needle.test(el.className)) el.className+=" "+targetclass },

showmenu:function(dropmenu, e){ if (this.enablereveal[0]){ if (!dropmenu._trueheight || dropmenu._trueheight<10) dropmenu._trueheight=dropmenu.offsetHeight clearTimeout(this.revealtimers[dropmenu.id]) dropmenu.style.height=dropmenu._curheight=0 dropmenu.style.overflow="hidden" dropmenu.style.visibility="visible" this.revealtimers[dropmenu.id]=setInterval(function(){cssdropdown.revealmenu(dropmenu)}, 10) } else{ dropmenu.style.visibility="visible" } this.css(this.asscmenuitem, "selected", "add") },

revealmenu:function(dropmenu, dir){ var curH=dropmenu._curheight, maxH=dropmenu._trueheight, steps=this.enablereveal[1] if (curH<maxH){ var newH=Math.min(curH, maxH) dropmenu.style.height=newH+"px" dropmenu._curheight= newH + Math.round((maxH-newH)/steps) + 1 } else{ //if done revealing menu dropmenu.style.height="auto" dropmenu.style.overflow="hidden" clearInterval(this.revealtimers[dropmenu.id]) } },

clearbrowseredge:function(obj, whichedge){ var edgeoffset=0 if (whichedge=="rightedge"){ var windowedge=document.all && !window.opera? this.standardbody.scrollLeft+this.standardbody.clientWidth-15 : window.pageXOffset+window.innerWidth-15 var dropmenuW=this.dropmenuobj.offsetWidth if (windowedge-this.dropmenuobj.x < dropmenuW) //move menu to the left? edgeoffset=dropmenuW-obj.offsetWidth } else{ var topedge=document.all && !window.opera? this.standardbody.scrollTop : window.pageYOffset var windowedge=document.all && !window.opera? this.standardbody.scrollTop+this.standardbody.clientHeight-15 : window.pageYOffset+window.innerHeight-18 var dropmenuH=this.dropmenuobj._trueheight if (windowedge-this.dropmenuobj.y < dropmenuH){ //move up? edgeoffset=dropmenuH+obj.offsetHeight if ((this.dropmenuobj.y-topedge)<dropmenuH) //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.hidemenu() //hide menu this.clearhidemenu() this.dropmenuobj=document.getElementById(dropmenuID) //reference drop down menu this.asscmenuitem=obj //reference associated menu item this.showmenu(this.dropmenuobj, 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" this.positionshim() //call iframe shim function },

positionshim:function(){ //display iframe shim function if (this.iframeshimadded){ if (this.dropmenuobj.style.visibility=="visible"){ this.shimobject.style.width=this.dropmenuobj.offsetWidth+"px" this.shimobject.style.height=this.dropmenuobj._trueheight+"px" this.shimobject.style.left=parseInt(this.dropmenuobj.style.left)+"px" this.shimobject.style.top=parseInt(this.dropmenuobj.style.top)+"px" this.shimobject.style.display="block" } } },

hideshim:function(){ if (this.iframeshimadded) this.shimobject.style.display='none' },

isContained:function(m, e){ var e=window.event || e var c=e.relatedTarget || ((e.type=="mouseover")? e.fromElement : e.toElement) while (c && c!=m)try {c=c.parentNode} catch(e){c=m} if (c==m) return true else return false },

dynamichide:function(m, e){ if (!this.isContained(m, e)){ this.delayhidemenu() } },

delayhidemenu:function(){ this.delayhide=setTimeout("cssdropdown.hidemenu()", this.disappeardelay) //hide menu },

hidemenu:function(){ this.css(this.asscmenuitem, "selected", "remove") this.dropmenuobj.style.visibility='hidden' this.dropmenuobj.style.left=this.dropmenuobj.style.top="-1000px" this.hideshim() },

clearhidemenu:function(){ if (this.delayhide!="undefined") clearTimeout(this.delayhide) },

addEvent:function(target, functionref, tasktype){ if (target.addEventListener) target.addEventListener(tasktype, functionref, false); else if (target.attachEvent) target.attachEvent('on'+tasktype, function(){return functionref.call(target, window.event)}); },

startchrome:function(){ if (!this.domsupport) return this.standardbody=(document.compatMode=="CSS1Compat")? document.documentElement : document.body 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") var asscdropdownmenu=document.getElementById(relvalue) this.addEvent(asscdropdownmenu, function(){cssdropdown.clearhidemenu()}, "mouseover") this.addEvent(asscdropdownmenu, function(e){cssdropdown.dynamichide(this, e)}, "mouseout") this.addEvent(asscdropdownmenu, function(){cssdropdown.delayhidemenu()}, "click") try{ menuitems[i].innerHTML=menuitems[i].innerHTML+" "+this.dropdownindicator }catch(e){} this.addEvent(menuitems[i], function(e){ //show drop down menu when main menu items are mouse over-ed if (!cssdropdown.isContained(this, e)){ var evtobj=window.event || e cssdropdown.dropit(this, evtobj, this.getAttribute("rel")) } }, "mouseover") this.addEvent(menuitems[i], function(e){cssdropdown.dynamichide(this, e)}, "mouseout") //hide drop down menu when main menu items are mouse out this.addEvent(menuitems[i], function(){cssdropdown.delayhidemenu()}, "click") //hide drop down menu when main menu items are clicked on } } //end inner for } //end outer for if (this.enableiframeshim && document.all && !window.XDomainRequest && !this.iframeshimadded){ //enable iframe shim in IE5.5 thru IE7? document.write('<IFRAME id="iframeshim" src="about:blank" frameBorder="0" scrolling="no" style="left:0; top:0; position:absolute; display:none;z-index:90; background: transparent;"></IFRAME>') this.shimobject=document.getElementById("iframeshim") //reference iframe object this.shimobject.style.filter='progid:DXImageTransform.Microsoft.Alpha(style=0,opacity=0)' this.iframeshimadded=true } } //end startchrome

}