DragObject

Question

function DragObject(){
this.currentX = 0;
this.currentY = 0;
this.id;
this.left = 0;
this.top = 0;
this.width = 125;
};
DragObject.prototype.initData = function() {
 var styleStr="<style type='text/css'>"+
"#"+this.id +"{"+
"position: absolute;"+
"left: "+this.left+";"+
"top: "+this.top+";"+
"width: "+this.width+";"+
"visibility: visible;"+
"z-index: 10;"+
"}"+
"</style>";
    //alert(styleStr);
document.write(styleStr);
};
function setActiveObject(elementObj){
currentObjId = elementObj.id;
}function saveXandY(elementObj){
if(whichIt != null){
elementObj.currentX = whichIt.offsetLeft;
elementObj.currentY = whichIt.offsetTop;
}else{
elementObj.currentX = 0;
elementObj.currentY = 0;
}
}self.onError=null;
currentX = currentY = 0;
whichIt = null;
lastScrollX = 0; 
lastScrollY = 0;
currentObjId = "floater";
NS = (document.layers) ? 1 : 0;
IE = (document.all) ? 1: 0;
function heartBeat() {
if(IE) { 
diffY = document.body.scrollTop; 
diffX = document.body.scrollLeft; 
}
if(NS) { 
diffY = self.pageYOffset; 
diffX = self.pageXOffset; 
}
if(diffY != lastScrollY) {
percent = .1 * (diffY - lastScrollY);
if(percent > 0){
percent = Math.ceil(percent);
}else{
percent = Math.floor(percent);
}
if(IE){ 
document.all.floater.style.pixelTop += percent;
}
if(NS){
document.floater.top += percent; 
}
lastScrollY = lastScrollY + percent;
}
if(diffX != lastScrollX) {
percent = .1 * (diffX - lastScrollX);
if(percent > 0){ 
percent = Math.ceil(percent);
}
else{
percent = Math.floor(percent);
}
if(IE){
document.all.floater.style.pixelLeft += percent;
}
if(NS){
document.floater.left += percent;
}
lastScrollX = lastScrollX + percent;
}
}
<!-- /STALKER CODE -->
<!-- DRAG DROP CODE -->
function checkFocus(x,y) { 
stalkerx = document.floater.pageX;
stalkery = document.floater.pageY;
stalkerwidth = document.floater.clip.width;
stalkerheight = document.floater.clip.height;
if((x > stalkerx && x < (stalkerx+stalkerwidth)) && (y > stalkery && y < (stalkery+stalkerheight))) 
return true;
else 
return false;
}function grabIt(e) {
//alert("abvc");
if(IE) {
whichIt = event.srcElement;
while (whichIt.id.indexOf(currentObjId) == -1) {
whichIt = whichIt.parentElement;
if (whichIt == null){ 
return true; 
}
}
whichIt.style.pixelLeft = whichIt.offsetLeft;
whichIt.style.pixelTop = whichIt.offsetTop;
currentX = (event.clientX + document.body.scrollLeft);
currentY = (event.clientY + document.body.scrollTop); 
}else{ 
window.captureEvents(Event.MOUSEMOVE);
if(checkFocus (e.pageX,e.pageY)) { 
whichIt = document.floater;
StalkerTouchedX = e.pageX-document.floater.pageX;
StalkerTouchedY = e.pageY-document.floater.pageY;
} 
}
return true;
}function moveIt(e) { if (whichIt == null) { 
return false; 
}
if(IE) {
newX = (event.clientX + document.body.scrollLeft);
newY = (event.clientY + document.body.scrollTop);
distanceX = (newX - currentX); distanceY = (newY - currentY);
currentX = newX; 
currentY = newY;
whichIt.style.pixelLeft += distanceX;
whichIt.style.pixelTop += distanceY;
if(whichIt.style.pixelTop < document.body.scrollTop){ 
whichIt.style.pixelTop = document.body.scrollTop;
}
if(whichIt.style.pixelLeft < document.body.scrollLeft){ 
whichIt.style.pixelLeft = document.body.scrollLeft;
}
if(whichIt.style.pixelLeft > document.body.offsetWidth - document.body.scrollLeft - whichIt.style.pixelWidth - 20){
whichIt.style.pixelLeft = document.body.offsetWidth - whichIt.style.pixelWidth - 20;
}
if(whichIt.style.pixelTop > document.body.offsetHeight + document.body.scrollTop - whichIt.style.pixelHeight - 5) {
whichIt.style.pixelTop = document.body.offsetHeight + document.body.scrollTop - 
whichIt.style.pixelHeight - 5;
}
event.returnValue = false;
} else { 
whichIt.moveTo(e.pageX-StalkerTouchedX,e.pageY-StalkerTouchedY);
if(whichIt.left < 0+self.pageXOffset){
whichIt.left = 0+self.pageXOffset;
}
if(whichIt.top < 0+self.pageYOffset){
whichIt.top = 0+self.pageYOffset;
}
if( (whichIt.left + whichIt.clip.width) >= (window.innerWidth+self.pageXOffset-17)) {
whichIt.left = ((window.innerWidth+self.pageXOffset)-whichIt.clip.width)-17;
}
if( (whichIt.top + whichIt.clip.height) >= (window.innerHeight+self.pageYOffset-17)) {
whichIt.top = ((window.innerHeight+self.pageYOffset)-whichIt.clip.height)-17;
}
return false;
}
return false;
}
function dropIt() {
whichIt = null;
if(NS) {
window.releaseEvents (Event.MOUSEMOVE);
}
return true;
}<!-- DRAG DROP CODE -->
if(NS) {
window.captureEvents(Event.MOUSEUP|Event.MOUSEDOWN);
window.onmousedown = grabIt;
window.onmousemove = moveIt;
window.onmouseup = dropIt;
}
if(IE) {
document.onmousedown = grabIt;
document.onmousemove = moveIt;
document.onmouseup = dropIt;
}
if(NS || IE) action = window.setInterval("heartBeat()",1);