//* Library created by habaj@ui42.sk 2007
//* 
//* 1-11-08 - Added id param - Peter Bolemant (bolemant@ui42.sk)


	function showOverlay( alpha, zindex, id ) 
	{
    if (id == undefined) id = "overlay";

		createOverlay(id);
		var overlay = document.getElementById(id);
		var style = overlay.style;
		var offs = getScrollXY();
		
		if( style.MozOpacity != undefined ) 
		{
			style.MozOpacity = alpha;
			overlay.style.width = window.innerWidth+offs[0]+"px";
			overlay.style.height = window.innerHeight+offs[1]+"px";
		}
		else if( style.filter != undefined ) 
		{
			style.filter = "alpha(opacity=0)";
			overlay.filters.alpha.opacity = ( alpha * 100 );
			overlay.style.width = document.body.offsetWidth+offs[0] + "px";
			overlay.style.height = document.body.offsetHeight+offs[1] + "px";
		}
		else if( style.opacity != undefined ) 
		{
			style.opacity = alpha;
			overlay.style.width = window.innerWidth+offs[0]+"px";
			overlay.style.height = window.innerHeight+offs[1]+"px";
		}
		overlay.style.display = "block";
		overlay.style.zIndex = zindex;
		getScrollXY();
		window.onscroll = refreshOverlayPos(id);
		window.onresize = refreshOverlaySize(id);
	}

	function hideOverlay(id) 
	{
    if (id == undefined) id = "overlay";
		var overlay = document.getElementById(id);

		overlay.style.display = "none";
		window.onscroll = null;
		window.onresize = null;
	}

	function getScrollXY() {
	  var scrOfX = 0, scrOfY = 0;
	  if( typeof( window.pageYOffset ) == 'number' ) {
	    //Netscape compliant
	    scrOfY = window.pageYOffset;
	    scrOfX = window.pageXOffset;
	  } else if( document.body && ( document.body.scrollLeft || document.body.scrollTop ) ) {
	    //DOM compliant
	    scrOfY = document.body.scrollTop;
	    scrOfX = document.body.scrollLeft;
	  } else if( document.documentElement && ( document.documentElement.scrollLeft || document.documentElement.scrollTop ) ) {
	    //IE6 standards compliant mode
	    scrOfY = document.documentElement.scrollTop;
	    scrOfX = document.documentElement.scrollLeft;
	  }
	  return [ scrOfX, scrOfY ];
	  
	}
	
	function refreshOverlayPos(id)
	{
    if (id == undefined) id = "overlay";
	
		var offs = getScrollXY();
		var overlay = document.getElementById(id);

		overlay.style.left = offs[0]+"px";	
		overlay.style.top = offs[1]+"px";	
	}
	
	function refreshOverlaySize(id)
	{
    if (id == undefined) id = "overlay";
	
		var overlay = document.getElementById(id);
		var style = overlay.style;
		var offs = getScrollXY();
				
		if( style.MozOpacity != undefined ) 
		{
			overlay.style.width = window.innerWidth+offs[0]+"px";
			overlay.style.height = window.innerHeight+offs[1]+"px";
		}
		else if( style.filter != undefined ) 
		{
			overlay.style.width = document.body.offsetWidth+offs[0] + "px";
			overlay.style.height = document.body.offsetHeight+offs[1] + "px";
		}
		else if( style.opacity != undefined ) 
		{
			overlay.style.width = window.innerWidth+offs[0]+"px";
			overlay.style.height = window.innerHeight+offs[1]+"px";
		}		
	}
	
	function createOverlay(id)
	{
    if (id == undefined) id = "overlay";
	
		var overlay = document.createElement("div");
		var style = overlay.style;
		var main = document.getElementById("main");
		style.display = "block";
		style.background = "black";
		style.position = "absolute";	
		style.top = "0px";
		style.left = "0px";
		
		overlay.setAttribute("id", id);
		
		main.appendChild(overlay);
	}
	
	function setOnMouseDown(func, id)
	{
    if (id == undefined) id = "overlay";
	
		var overlay = document.getElementById(id);
		overlay.onmousedown = func;
	}