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

//암전켜기
function back_bg_on(obj){

	//암전
	var documentwidth = $(document).width();
	var documentheight = $(document).height();
	$("#back_bg").css({"position":"absolute","width":documentwidth,"height":documentheight,"z-index":"1000","left":"0px","top":"0px","background":"#000000"}).fadeTo("show",0.7);
	$("#back_bg").bind("click",function(){
		back_bg_off(obj);
	})

	//내용물
	$("#"+obj).css({"position":"absolute","z-index":"1001"});
	var objwidth = $("#"+obj).width();
	var objheight = $("#"+obj).height();
	var h = $(window).height()/2 - objheight/2;
	var position = $(window).scrollTop();

	$("#"+obj).css({"left":(documentwidth/2)-(objwidth/2),"top":position+h});
	$("#"+obj).fadeTo("show",1);


}
//암전끄기
function back_bg_off(obj){
	$("#back_bg").css({"position":"absolute","width":"100%","height":"100%","z-index":"1000","left":"0px","top":"0px","background":"#000000"}).hide();
	$("#"+obj).hide();
}