/**

 * this function dims the visible browser window to 50% and locks. 

 * it also buts a layer with the given name and dimensions in the middle where some ajax-request can be loaded in 

 * layerName has to be given as jquery ID or class name which means there has to be a hash-sign or a dot in front of the name

 * 

 * @param string layerName - ID of some targetArea

 * @param int layerWidth - Width of targetArea

 * @param int layerHeight - Height of targetArea

 * @param bool fadeIn

 * @return no return

 */

function layerOverlayDim(layerName, layerWidth, layerHeight, layerHeightAuto, fadeIn)

{

    if(fadeIn === undefined || fadeIn === '')

    {

		fadeIn = true;

    }	

    

    if(layerHeightAuto == true)

    {

	var layerHeightStr = "auto"

    }

    else

    {

	var layerHeightStr = layerHeight + "px"

    }

    

	$("body").css("overflow", "hidden");

	

	var y = centerLayerY(layerHeight);

	

	$(layerName).css

	(

		{

		    "top" : y + "px",

		    "height" : layerHeightStr,

		    "width" : layerWidth + "px",

		    "margin-left" : - ( layerWidth / 2 ) + "px",

		    "position" : "absolute",

		    "left" : "50%",

		    "z-index" : "21000"

		}

	);

	

	if(fadeIn === true)

	{

	    $(layerName).fadeIn();

	}

	else

	{

		$(layerName).show();

	}



	getOverlay();

}





/**

 * this funktion makes the whole magic disappear

 * @return no return

 */

function closeLayerOverlayDim()

{

    $("body").css("overflow", "auto");

    $("#overlay").empty().hide();

}





var dim_c = 0;

var dim_t;

function dimOverlay()

{

    $("#overlay").show();

	  

	dim_c = dim_c + 1;

	dim_t = setTimeout("dimOverlay()", 100);



	$("#overlay").css("opacity", dim_c / 10);

	$("#overlay").css("filter", "alpha(opacity: " + (dim_c * 10) + ")");

	

	if(dim_c == 6)

	{

		clearTimeout(dim_t);

		dim_c = 0;

	}

}





function centerLayerY(layerheight)

{

	var currentTop = $(window).scrollTop();

	var winheight = $(window).height();

	

	var yMiddleA = winheight / 2;

	var yMiddleB = layerheight / 2;



	if(layerheight > winheight)

	{

		return currentTop + 5;

	}	

	else

	{

	    return currentTop + yMiddleA - yMiddleB;

	}					

}





function getOverlay()

{

    var currentTop = $(window).scrollTop();

    var winheight = $(window).height();

    var winwidth = $(window).width();

    

    $("#overlay").css

    (

	    {

		"width" : winwidth + 100,

		"height" : winheight + 100,

		"background-color" : "#f8f8f8",

		"z-index" : "20000",

		"position" : "absolute",

		"top" : currentTop,

		"left" : "0",

		"opacity" : "0",

		"filter" : "alpha(opacity: 0)"

	    }

    );



    dimOverlay();

}



//document.write('<div class="overlay" id="overlay" style="display: none;"></div>');