function DragDrop(elem, handles, settings){
	this.elem = elem;
	this.elem.oThis = this;
	this.handles = handles;
	this.settings = (settings) ? settings : DragDrop.defaultSettings;	
	if(settings){
		for(var i in DragDrop.defaultSettings){
			if(typeof this.settings[i] == 'undefined'){
				this.settings[i] = DragDrop.defaultSettings[i];
			}
		}//for
	}
	this.prevX = 0;
	this.prevY = 0;

	this.deltaX = 0;
	this.deltaY = 0;
	
	this.draggedX = this.settings.startPosX;
	this.draggedY = this.settings.startPosY;
	
	this.stopLeft = false;
	this.stopRight = false;
	this.stopUp = false;
	this.stopDown = false;

	this.isMoving = false;

	this.onmove = null;
	this.onstart = null;
	this.onstop = null;

	this.init();
}
DragDrop.defaultSettings = {
	dragX: true,
	dragY: true,
	moveSpaceX: -1,
	moveSpaceY: -1,
	startPosX: 0,
	startPosY: 0
}
DragDrop.prototype.init = function(){
	this.initElem();
	this.initHandles();
	this.setFlags();
	this.initMouseDown();
}
DragDrop.prototype.initElem = function(){
	if(typeof this.elem == 'string'){
		this.elem = document.getElementById(this.elem);
	}
}
DragDrop.prototype.initHandles = function(){
	if(typeof this.handles == 'string'){
		var arrHandles = [];
		var handlesClass = this.handles;
		var children = getAllChildren(this.elem);
		var showFunc = function(obj){
			if(obj.type == 1){
				if(obj.elem.className.indexOf(handlesClass) != -1){
					arrHandles.push(obj.elem);
				}
			}
		}
		showAllChildren(children, showFunc);
		this.handles = arrHandles;
	}else if(typeof this.handles == 'object' && typeof this.handles.length == 'undefined'){
		var arrHandles = [];
		arrHandles.push(this.handles);
		this.handles = arrHandles;
	}
		
}
DragDrop.prototype.setFlags = function(){
	if(this.settings.moveSpaceX >= 0){
		if(this.settings.moveSpaceX == 0){
			this.stopLeft = true;
			this.stopRight = true;
		}
		if(this.draggedX == 0){
			this.stopLeft = true;
		}else if(this.draggedX == this.settings.moveSpaceX){
			this.stopRight = true;
		}
	}
	if(this.settings.moveSpaceY >= 0){
		if(this.settings.moveSpaceY == 0){
			this.stopUp = true;
			this.stopDown = true;
		}
		if(this.draggedY == 0){
			this.stopUp = true;
		}else if(this.draggedY == this.settings.moveSpaceY){
			this.stopDown = true;
		}
	}

}
DragDrop.prototype.initMouseDown = function(){
	this.isMoving = true;
	var oThis = this;
	this.elem.style.position = 'absolute';
	for(var i = 0; i < this.handles.length; i++){
		var handle = this.handles[i];
		handle.onmousedown = this.start;
	}
}
DragDrop.prototype.checkMoveSpace = function(deltaX, deltaY){
	var dX = deltaX;
	var dY = deltaY;
	var retArr = [];

	//check X
	//Left
	if(this.settings.moveSpaceX >= 0){
		if(this.stopLeft){
			if(deltaX <= 0){
				dX = 0;
			}else{
				this.stopLeft = false;
			}
		}	
		//Right
		if(this.stopRight){
			if(deltaX >= 0){
				dX = 0;
			}else{
				this.stopRight = false;
			}
		}
		if(this.draggedX + deltaX >= this.settings.moveSpaceX){
			dX = this.settings.moveSpaceX - this.draggedX;
			this.stopRight = true;
		}

		if(this.draggedX + deltaX <= 0){
			dX = -this.draggedX;
			this.stopLeft = true;
		}
	}
		
	//checkY
	if(this.settings.moveSpaceY >= 0){
	//Up
		if(this.stopUp){
			if(deltaY <= 0){
				dY = 0;
			}else{
				this.stopUp = false;
			}
		}	
		if(this.stopDown){
			if(deltaY >= 0){
				dY = 0;
			}else{
				this.stopDown = false;
			}
		}
//setting Flags
		if(this.draggedY + deltaY >= this.settings.moveSpaceY){
			dY = this.settings.moveSpaceY - this.draggedY;
			this.stopDown = true;
		}
		if(this.draggedY + deltaY <= 0){
			dY = -this.draggedY;
			this.stopUp = true;
		}
	}
	
	//X

	retArr.push(dX);
	retArr.push(dY);
	return retArr;
}
DragDrop.prototype.move = function(currentX, currentY){
	var deltaY = currentY - this.prevY;
	var deltaX = currentX - this.prevX;
	this.moveBy(deltaX, deltaY);
	this.prevX = currentX;
	this.prevY = currentY;
}
DragDrop.prototype.moveBy = function(deltaX, deltaY){
	var newDelta = this.checkMoveSpace(deltaX, deltaY);
	deltaX = newDelta[0];
	deltaY = newDelta[1];
	var left = this.elem.offsetLeft + deltaX;
	var top = this.elem.offsetTop + deltaY;
	this.elem.style.left = left + 'px';
	this.elem.style.top = top + 'px';

	this.draggedX += deltaX;
	this.draggedY += deltaY;

	this.deltaX = deltaX;
	this.deltaY = deltaY;
	//event handlers
	if(this.onmove){
		this.onmove.func.apply(this.onmove.oThis, this.onmove.args);
	}
}

DragDrop.prototype.start = function(e){
	var oThis = GetThis(this, 'oThis');
	var ev = window.event || e;
	oThis.prevX = ev.clientX;
	oThis.prevY = ev.clientY;
	document.onmousemove = function(e){
		var ev = window.event || e;
		var currentX = ev.clientX;
		var currentY = ev.clientY;
		oThis.move.apply(oThis, [currentX, currentY]);
	}
	document.onmouseup = function(){
		oThis.stop.call(oThis);
	}
	//event handlers
	if(oThis.onstart){
		oThis.onstart.func.apply(oThis.onstart.oThis, oThis.onstart.args);
	}
}
DragDrop.prototype.stop = function(){
	document.onmousemove = null;
	document.onmouseup = null;
	this.isMoving = false;
	if(this.onstop){
		this.onstop.func.apply(this.onstop.oThis, this.onstop.args);
	}
}