JavaScript Draggable Drop Text Layer

<style>

.dragDrop
{
position:absolute;
color:#FFFFFF;
font-family:Arial;
font-size:10pt;
font-weight:bold;
z-index:0;
}
</style>

<script language="JavaScript">
<!--

function TElement(id)
{
this.id=id;
this.elt=(this.id) ? document.getElementById(id) : null;

function getX()
{
return this.elt.offsetLeft;
}
TElement.prototype.getX=getX;

function getY()
{
return this.elt.offsetTop;
}
TElement.prototype.getY=getY;

function setX(x)
{
return this.elt.style.left=x+"px";
}
TElement.prototype.setX=setX;

function setY(y)
{
return this.elt.style.top=y+"px"
}
TElement.prototype.setY=setY;

}

function TEvent()
{
this.x = 0;
this.y = 0;

function init(evt)
{
this.evt=(evt) ? evt : window.event; // l'objet événement
if (!this.evt) return;
this.elt=(this.evt.target) ? this.evt.target : this.evt.srcElement; // la source de l'événement

this.id=(this.elt) ? this.elt.id : "";

// Calcul des coordonnées de la souris par rapport au document

if (this.evt.pageX || this.evt.pageY)
{
this.x = this.evt.pageX;
this.y = this.evt.pageY;
}
else if (this.evt.clientX || this.evt.clientY)
{
this.x = this.evt.clientX + document.body.scrollLeft;
this.y = this.evt.clientY + document.body.scrollTop;
}
}
TEvent.prototype.init=init;

function stop()
{
this.evt.cancelBubble = true;
if (this.evt.stopPropagation) this.evt.stopPropagation();
}
TEvent.prototype.stop=stop;
}

function TDragObject(id)
{
if (!id) return;
this.base=TElement;

this.base(id);
this.elt.obj=this
this.elt.onmousedown=_startDrag;

function startDrag(evt)
{
this.elt.style.zIndex=1;
this.lastMouseX=evt.x;
this.lastMouseY=evt.y;
evt.dragObject=this;

document.onmousemove=_drag;
document.onmouseup=_stopDrag;

if (this.onStartDrag) this.onStartDrag();
}
TDragObject.prototype.startDrag=startDrag;

function stopDrag(evt)
{
this.elt.style.zIndex=0;
evt.dragObject=null;
document.onmousemove=null;
document.onmouseup=null;

if (this.onDrop) this.onDrop();
}
TDragObject.prototype.stopDrag=stopDrag;

function drag(evt)
{
dX=this.getX()+evt.x-this.lastMouseX;
dY=this.getY()+evt.y-this.lastMouseY;

this.setX(dX);
this.setY(dY);

this.lastMouseX=evt.x;
this.lastMouseY=evt.y;

if (this.onDrag) this.onDrag();

}
TDragObject.prototype.drag=drag;
}
TDragObject.prototype=new TElement();

var _event=new TEvent(); // Objet global pour manipuler l'événement en cours

function _startDrag(evt)
{
_event.init(evt);
if (this.obj && this.obj.startDrag)
{
this.obj.startDrag(_event);
}
}

function _stopDrag(evt)
{
if (_event.dragObject) _event.dragObject.stopDrag(_event);
}

function _drag(evt)
{
_event.init(evt);
if (_event.dragObject) _event.dragObject.drag(_event);
return false;
}

function afficherStatus()
{
window.status="Object ["+this.id+"] se trouve en ("+this.getX()+","+this.getY()+")"+
" text =\""+this.elt.innerHTML+"\"";
}

function load()
{
tst=new TDragObject("test");
tst.onDrag=afficherStatus;

tst2=new TDragObject("test2");
tst2.onDrag=afficherStatus;
}

// -->
</script>