//** DD Drop Down Panel- (c) Dynamic Drive DHTML code library: http://www.dynamicdrive.com
//** Oct 21st, 08'- Script created
//** March 23rd, 09' v1.01- Arrow images now preloaded

function ddpanel(setting){
	setting.dir="up" //initial state of panel (up="contracted")
	if (setting.stateconfig.persiststate && ddpanel.getCookie(setting.ids[0])=="down"){
		setting.dir="down"
	}
	if (setting.dir=="up"){ //if "up", output CSS to hide panel contents
		document.write('<style type="text/css">\n')
		document.write('#'+setting.ids[1]+'{height:' + parseInt(setting.stateconfig.initial) + 'px; overflow:hidden}\n')
		document.write('</style>\n')
	}
	setting.stateconfig.initial=parseInt(setting.stateconfig.initial)
	this.setting=setting
	if (setting.pointerimage.enabled){ //preload images
		var img1=new Image(), img2=new Image()
		img1.src=setting.pointerimage.src[0]
		img2.src=setting.pointerimage.src[1]
	}
	var thispanel=this
	if (window.addEventListener) //if non IE browsers, initialize panel window.onload
		ddpanel.addEvent(window, function(e){thispanel.initpanel(setting)}, "load")
	else //else if IE, add 100 millisec after window.onload before initializing
		ddpanel.addEvent(window, function(e){setTimeout(function(){thispanel.initpanel(setting)}, 100)}, "load")
	ddpanel.addEvent(window, function(e){thispanel.uninit(setting)}, "unload")
}

ddpanel.events_array=[] //object array to contain events created by script

ddpanel.addEvent=function(target, functionref, tasktype){
	var evtmodel=target.addEventListener? "w3c" : "ie"
	var evtaction=evtmodel=="w3c"? "addEventListener" : "attachEvent"
	var i=this.events_array.push({ //store event info in ddpanel.events_array[] and return current event's index within array
		target: target,
		tasktype: (evtmodel=="ie"? "on" : "")+tasktype,
		listener: evtmodel=="ie"? function(){return functionref.call(target, window.event)} : functionref
	})-1
	target[evtaction](this.events_array[i].tasktype, this.events_array[i].listener, evtmodel=="w3c"? false : null)
}

ddpanel.removeEvent=function(target, functionref, tasktype){
	var evtmodel=target.removeEventListener? "w3c" : "ie"
	var evtaction=evtmodel=="w3c"? "removeEventListener" : "detachEvent"
	target[evtaction](tasktype, functionref, evtmodel=="w3c"? false : null)
}

ddpanel.getCookie=function(Name){ 
	var re=new RegExp(Name+"=[^;]+", "i"); //construct RE to search for target name/value pair
	if (document.cookie.match(re)) //if cookie found
		return document.cookie.match(re)[0].split("=")[1] //return its value
	return null
}

ddpanel.setCookie=function(name, value){
	document.cookie = name+"=" + value + ";path=/"
}

ddpanel.addpointer=function(target, className, imagesrc){
	var pointer=document.createElement("img")
	pointer.src=imagesrc
	pointer.className=className
	pointer.style.borderWidth=0
	target.appendChild(pointer)
	return pointer
}

ddpanel.prototype={

togglepanel:function(dir){ //public function that toggles the panel's state. Optional dir parameter ("up" or "down") to explicitly set state.
	var setting=this.setting
	setting.dir=dir || ((setting.dir=="up")? "down" : "up")
	var pcontent=setting.pcontent, dir=setting.dir
	pcontent._currentheight=(dir=="down")? pcontent._actualheight : setting.stateconfig.initial
	pcontent.style.height=pcontent._currentheight+"px"
	if (setting.pointerimage.enabled){
		setting.arrow.src=setting.pointerimage.src[(setting.dir=="down")? 1 : 0]
		setting.arrow.style.visibility="visible"
	}
	ddpanel.setCookie(setting.ids[0], setting.dir)
},

togglepanelplus:function(dir){ //public function that toggles the panel's state w/ animation. Optional dir parameter ("up" or "down") to explicitly set state.
	var setting=this.setting
	setting.dir=dir || ((setting.dir=="up")? "down" : "up")
	if (setting.pointerimage.enabled)
		setting.arrow.style.visibility="hidden"
	clearTimeout(setting.revealtimer)
	this.revealcontent()
},

revealcontent:function(){
	var setting=this.setting
	var pcontent=setting.pcontent, curH=pcontent._currentheight, maxH=pcontent._actualheight, minH=setting.stateconfig.initial, steps=setting.animate.steps, dir=setting.dir
	if (dir=="down" && curH<maxH || dir=="up" && curH>minH){
		var newH = curH + (Math.round((maxH-curH)/steps)+1) * (dir=="up"? -1 : 1)
		newH=(dir=="down")? Math.min(maxH, newH) : Math.max(minH, newH)
		pcontent.style.height=newH+"px"
		pcontent._currentheight=newH
	}
	else{
		if (setting.pointerimage.enabled){
			setting.arrow.src=setting.pointerimage.src[(setting.dir=="down")? 1 : 0]
			setting.arrow.style.visibility="visible"
		}
		return
	}
	var thispanel=this
	setting.revealtimer=setTimeout(function(){thispanel.revealcontent()}, 10)
},

initpanel:function(){
	var setting=this.setting
	var pcontainer=setting.pcontainer=document.getElementById(setting.ids[0])
	var pcontent=setting.pcontent=document.getElementById(setting.ids[1])
	var tdiv=setting.tdiv=document.getElementById(setting.ids[2])
	pcontent.style.overflow="scroll"
	pcontent._actualheight=pcontent.scrollHeight
	setTimeout(function(){pcontent._actualheight=pcontent.scrollHeight}, 100)
	pcontent.style.overflow="hidden"
	pcontent._currentheight=(setting.dir=="down")? pcontent._actualheight : setting.stateconfig.initial
	var thispanel=this
	ddpanel.addEvent(tdiv, function(e){ //assign click behavior when toggle DIV tab is clicked on
		if (setting.animate.enabled)
			thispanel.togglepanelplus()
		else
			thispanel.togglepanel()
		if (e.preventDefault) e.preventDefault()
		return false
	}, "click")
	if (setting.pointerimage.enabled){
		var pointer1=new Image(), pointer2=new Image()
		pointer1.src=setting.pointerimage.src[0]
		pointer2.src=setting.pointerimage.src[1]
		setting.arrow=ddpanel.addpointer(tdiv.getElementsByTagName("span")[0], "pointerimage", setting.pointerimage.src[setting.dir=="down"? 1:0])
	}
	if (setting.closepanelonclick.enabled){ //assign click behavior when panel content is clicked on (links within panel or elements with class "closepanel"
			ddpanel.addEvent(pcontent, function(e){
				var target=e.srcElement || e.target
				if (/(^|\s+)closepanel($|\s+)/.test(target.className) || target.tagName=="A" || (target.parentNode && target.parentNode.tagName=="A")){
					thispanel.togglepanel("up")
				}
			}, "click")
	}
},

uninit:function(){
	var setting=this.setting
	if (setting.stateconfig.persiststate){
		ddpanel.setCookie(setting.ids[0], setting.dir)
	}
	for (prop in setting){
		setting[prop]=null
	}
}



} //end of ddpanel object


//initialize instance of DD Drop Down Panel:

var defaultpanel=new ddpanel({
	ids: ["mypanel", "mypanelcontent", "mypaneltab"], // id of main panel DIV, content DIV, and tab DIV
	stateconfig: {initial: "0px", persiststate: true}, // initial: initial reveal amount in pixels (ie: 5px)
	animate: {enabled: true, steps: 5}, //steps: number of animation steps. Int between 1-20. Smaller=faster.
	pointerimage: {enabled: true, src: ["images/arrow-down.gif", "images/arrow-up.gif"]},
	closepanelonclick: {enabled: true} // close panel when links or elements with CSS class="closepanel" within container is clicked on?
})