/// Drag&Drop System

	var dragobj;
	
	function m_down(event, object)
	{
	
		
		dragobj = object;      
		
		dragobj.style.zIndex = "100";	
		if(!dragobj.style.left) dragobj.style.left = "0px";
		if(!dragobj.style.top) dragobj.style.top = "0px";
			
		// Zapamatuj pozici mysi pri klintuti
		dragobj.clickX = event.clientX;  
		dragobj.clickY = event.clientY;
			
		// Zapamatuj pozici objektu pri klintuti
		dragobj.left = parseInt(dragobj.style.left); 
		dragobj.top = parseInt(dragobj.style.top);


	 	// Zacni sledovat pohyb mysi
    if(IE)
		{	
			document.attachEvent('onmousemove', m_move); 
			document.attachEvent('onmouseup', m_up); 		
		}
	
		if(NS || OPERA) 
		{
			document.addEventListener('mousemove', m_move, true);
			document.addEventListener('mouseup', m_up, true); 		
		}

return stopEvent(event);
}


function m_move(event)
{
	// Spocti rozdil mezi puvodni pozici mysi pri stisku a nynejsi pozici a zavolej proceduru objektu pro presun 
	dragobj.ondragdrop(event.clientX-dragobj.clickX,event.clientY-dragobj.clickY, event);
	return stopEvent(event);
}

function m_up(event)
{
	// Ukonci sledovani mysi
	if(IE)
	{
		document.detachEvent('onmousemove', m_move); 	
		document.detachEvent('onmouseup', m_up); 
		if(dragobj.ondragend)dragobj.ondragend(event);
	}

	if(NS || OPERA)
	{
		document.removeEventListener('mousemove', m_move, true); 
		document.removeEventListener('mouseup', m_up, true);
		if(dragobj.ondragend)dragobj.ondragend(event);
	}

	return stopEvent(event);	
}


// Prirad objektu moznost presunu
function startDrag(what)
{
	if(what.style.position!="relative" && what.style.position!="absolute") {what.style.position="absolute";}
	what.onmousedown = function(e) {if(e) {event=e;} m_down(event,what);}
	what.drag = 1;
}

// Odeber objektu moznost presunu 
function stopDrag(what)
{
	what.onmousedown = null;
	what.drag = 0;
}

// Zastav sireni udalosti
function stopEvent(event)
{
	if(IE) {event.cancelBubble = true; return false;}
	if(NS || OPERA) {event.stopPropagation(); event.preventDefault(); return false;}
}