//Animated Collapsible DIV- Author: Dynamic Drive (http://www.dynamicdrive.com)
//Last updated Aug 1st, 07'. Fixed bug with "block" parameter not working when persist is enabled
//Updated June 27th, 07'. Added ability for a DIV to be initially expanded.

var uniquepageid=window.location.href.replace("http://"+window.location.hostname, "").replace(/^\//, "") //get current page path and name, used to uniquely identify this page for persistence feature

function animatedcollapse(divId, animatetime, persistexpand, initstate){
 this.divId=divId
 this.divObj=document.getElementById(divId)
 this.divObj.style.overflow="hidden"
 this.timelength=animatetime
 this.initstate=(typeof initstate!="undefined" && initstate=="block")? "block" : "contract"
 this.isExpanded="no"; //animatedcollapse.getCookie(uniquepageid+"-"+divId) //"yes" or "no", based on cookie value
 this.contentheight=parseInt(this.divObj.style.height)
 var thisobj=this
 if (isNaN(this.contentheight)){ //if no CSS "height" attribute explicitly defined, get DIV's height on window.load
  animatedcollapse.dotask(window, function(){thisobj._getheight(persistexpand)}, "load")
  if (!persistexpand && this.initstate=="contract" || persistexpand && this.isExpanded!="yes" && this.isExpanded!="") //Hide DIV (unless div should be expanded by default, OR persistence is enabled and this DIV should be expanded)
   this.divObj.style.visibility="hidden" //hide content (versus collapse) until we can get its height
 }
 else if (!persistexpand && this.initstate=="contract" || persistexpand && this.isExpanded!="yes" && this.isExpanded!="") //Hide DIV (unless div should be expanded by default, OR persistence is enabled and this DIV should be expanded)
  this.divObj.style.height=0 //just collapse content if CSS "height" attribute available
 //if (persistexpand)
 // animatedcollapse.dotask(window, function(){animatedcollapse.setCookie(uniquepageid+"-"+thisobj.divId, thisobj.isExpanded)}, "unload")
}

animatedcollapse.prototype._getheight=function(persistexpand){
 this.contentheight=this.divObj.offsetHeight
 if (!persistexpand && this.initstate=="contract" || persistexpand && this.isExpanded!="yes"){ //Hide DIV (unless div should be expanded by default, OR persistence is enabled and this DIV should be expanded)
  this.divObj.style.height=0 //collapse content
  this.divObj.style.visibility="visible"
 }
 else //else if persistence is enabled AND this content should be expanded, define its CSS height value so slideup() has something to work with
  this.divObj.style.height=this.contentheight+"px"
}


animatedcollapse.prototype._slideengine=function(direction){
 var elapsed=new Date().getTime()-this.startTime //get time animation has run
 var thisobj=this
 if (elapsed<this.timelength){ //if time run is less than specified length
  var distancepercent=(direction=="down")? animatedcollapse.curveincrement(elapsed/this.timelength) : 1-animatedcollapse.curveincrement(elapsed/this.timelength)
 this.divObj.style.height=distancepercent * this.contentheight +"px"
 this.runtimer=setTimeout(function(){thisobj._slideengine(direction)}, 10)
 }
 else{ //if animation finished
  this.divObj.style.height=(direction=="down")? this.contentheight+"px" : 0
  this.isExpanded=(direction=="down")? "yes" : "no" //remember whether content is expanded or not
  this.runtimer=null
 }
}


animatedcollapse.prototype.slidedown=function(){
 if (typeof this.runtimer=="undefined" || this.runtimer==null){ //if animation isn't already running or has stopped running
  if (isNaN(this.contentheight)) //if content height not available yet (until window.onload)
   alert("Please wait until document has fully loaded then click again")
  else if (parseInt(this.divObj.style.height)==0){ //if content is collapsed
   this.startTime=new Date().getTime() //Set animation start time
   this._slideengine("down")
  }
 }
}

animatedcollapse.prototype.slideup=function(){
 if (typeof this.runtimer=="undefined" || this.runtimer==null){ //if animation isn't already running or has stopped running
  if (isNaN(this.contentheight)) //if content height not available yet (until window.onload)
   alert("Please wait until document has fully loaded then click again")
  else if (parseInt(this.divObj.style.height)==this.contentheight){ //if content is expanded
   this.startTime=new Date().getTime()
   this._slideengine("up")
  }
 }
}

animatedcollapse.prototype.slideit=function(){
 if (isNaN(this.contentheight)) //if content height not available yet (until window.onload)
  alert("Please wait until document has fully loaded then click again")
 else if (parseInt(this.divObj.style.height)==0)
  this.slidedown()
 else if (parseInt(this.divObj.style.height)==this.contentheight)
  this.slideup()
}

// -------------------------------------------------------------------
// A few utility functions below:
// -------------------------------------------------------------------

animatedcollapse.curveincrement=function(percent){
 return (1-Math.cos(percent*Math.PI)) / 2 //return cos curve based value from a percentage input
}

animatedcollapse.dotask=function(target, functionref, tasktype){ //assign a function to execute to an event handler (ie: onunload)
 var tasktype=(window.addEventListener)? tasktype : "on"+tasktype
 if (target.addEventListener)
  target.addEventListener(tasktype, functionref, false)
 else if (target.attachEvent)
  target.attachEvent(tasktype, functionref)
}