// JavaScript Document
/***********************************************
* Dock Content script- Created by and © Dynamicdrive.com
* This notice must stay intact for use
* Visit http://www.dynamicdrive.com/ for full script
***********************************************/

var offsetfromedge=0      //offset from window edge when content is "docked". Change if desired.
var dockarray=new Array() //array to cache dockit instances
var dkclear=new Array()   //array to cache corresponding clearinterval pointers

function dockit(el, duration){
this.source=document.all? document.all[el] : document.getElementById(el);
this.source.height=this.source.offsetHeight;
this.docheight=truebody().clientHeight;
this.duration=duration;
this.pagetop=0;
this.elementoffset=this.getOffsetY();
dockarray[dockarray.length]=this;
var pointer=eval(dockarray.length-1);
var dynexpress='dkclear['+pointer+']=setInterval("dockornot(dockarray['+pointer+'])",100);';
dynexpress=(this.duration>0)? dynexpress+'setTimeout("clearInterval(dkclear['+pointer+']); dockarray['+pointer+'].source.style.top=0", duration*1000)' : dynexpress;
eval(dynexpress);
}

dockit.prototype.getOffsetY=function(){
var totaloffset=parseInt(this.source.offsetTop);
var parentEl=this.source.offsetParent;
while (parentEl!=null){
totaloffset+=parentEl.offsetTop;
parentEl=parentEl.offsetParent;
}
return totaloffset;
}

function dockornot(obj){
/*obj.pagetop=truebody().scrollTop;
if (obj.pagetop>obj.elementoffset) //detect upper offset
obj.source.style.top=obj.pagetop-obj.elementoffset+offsetfromedge+"px";
else if (obj.pagetop+obj.docheight<obj.elementoffset+parseInt(obj.source.height)) //lower offset
obj.source.style.top=obj.pagetop+obj.docheight-obj.source.height-obj.elementoffset-offsetfromedge+"px";
else*/
obj.source.style.top=0;
}

function truebody(){
return (document.compatMode && document.compatMode!="BackCompat")? document.documentElement : document.body
}
<!--scripts/dock.js-->