function bloquearPagina(ColorFondo){
	
	if(ColorFondo==undefined)
		ColorFondo="white";
	var Imagen=new Array();
	Imagen[0]="BannerC2012.jpg";
	//Imagen[1]="escudo-unam-100px.jpg";
	pantalla="<div id='msgPantalla' style='color:#ffffff;background-color: "+ ColorFondo + ";visibility: visible; position: absolute;z-index: 5;opacity: 0.90;filter:progid:DXImageTransform.Microsoft.Alpha(opacity=90);width:100%;height:100%;vertical-align:middle;top:0;' valign='middle'>";
	pantalla+="<table border='0' width='100%' height='100%'>";
	pantalla+="<tr valign='middle'><td>";
	pantalla+="<table style='position:relative;background-color: rgb(0, 0, 102); color:#ffffff;width: 810px; height: 150px; ' border='1' cellpadding='10' cellspacing='10' valign='middle' align='center'>";
	pantalla+="<tbody><tr><td align='center' style='font-size: 15px;font-weight: bold;'>";
	//pantalla+="ESPERE UN MOMENTO<br>Cargando Pagina...";
	IndiceImag=aleatorio(0,(Imagen.length - 1 ));
	
	pantalla+="<img src='../Datos/bannerespera/" + Imagen[IndiceImag] + "' >\n";
	pantalla+="</td></tr></tbody></table>";
	pantalla+="</td></tr></table>";
	pantalla+="</div>"
	
	Ancho=(screen.width - 360)/3;
	Alto=(screen.height - 150)/3;;
	pantalla+="<div id='msgBanner' style='color:#ffffff;visibility: hidden; position: absolute;z-index: 5;opacity: 0.75;filter:progid:DXImageTransform.Microsoft.Alpha(opacity=75);width:350;height:150;vertical-align:middle;top:" + Alto + "px;left:" + Ancho + "px'>";
	pantalla+="<table border='0' width='350px' height='150px' align='center'>";
	pantalla+="<tr valign='middle'><td>";
	pantalla+="<table style='position:relative;background-color: rgb(0, 0, 102); color:#ffffff;width: 350px; height: 150px; ' border='1' cellpadding='10' cellspacing='10' valign='middle' align='center'>";
	pantalla+="<tbody><tr><td align='center' style='font-size: 15px;font-weight: bold;'>";
	pantalla+="<p onclick='JavaSript:document.getElementById(\"msgBanner\").style.visibility=\"hidden\";' align='right'>[Cerrar]</p>"
	pantalla+="CONFERENCIA MAGISTRAL<br>";
	pantalla+="EL \"ABC\" DE LAC COAGULACION<br>";
	pantalla+="JUEVES 15 DE ENERO 2009  a las 17:00<br>";
	pantalla+="ENTRADA LIBRE<br>";
	pantalla+="</td></tr></tbody></table>";
	pantalla+="</td></tr></table>";
	pantalla+="</div>"
	/*
	pantalla+="<div id='msgMensajesInstantaneos' style='color:#ffffff;visibility: visible; position: absolute;z-index: 15;opacity: 0.75;filter:progid:DXImageTransform.Microsoft.Alpha(opacity=75);width:50;height:50;vertical-align:middle;top:1200px;left:0px'>";
	pantalla+="<table border='0' width='50px' height='50px' align='center'>";
	pantalla+="<tr valign='middle'><td>";
	pantalla+="<iframe width='50' height='50' src='mensajes.php' ></iframe>";
	pantalla+="</td></tr></table>";
	pantalla+="</div>"
	*/
	document.write(pantalla);
}

function aleatorio(inferior,superior){
	numPosibilidades = superior - inferior
	aleat = Math.random() * numPosibilidades
	aleat = Math.round(aleat)
	if(aleat>superior)
		aleat=superior;
	/*if(aleat<inferior)
		aleat=inferior;
		*/
	return parseInt(inferior) +  aleat
	} 

function ActivarBanner(){
	//setTimeout("document.getElementById('msgBanner').style.visibility='visible';",100);
	//setTimeout("document.getElementById('msgBanner').style.visibility='hidden';",6000);
}
function aclararPagina(intervalo,Banner){
	var opacidad="";

	if(intervalo<13){
		
		opacidad+="document.getElementById('msgPantalla').style.opacity=" + (0.85 - (.05 * intervalo)) + ";";
		opacidad+="document.getElementById('msgPantalla').style.filter='progid:DXImageTransform.Microsoft.Alpha(opacity=" + (85 - (5 * intervalo)) + ")';";
		opacidad+="aclararPagina(" + (intervalo + 1) + ");";
		setTimeout(opacidad,70);
	}else{
		
		if(Banner==true)
			setTimeout("document.getElementById('msgPantalla').style.visibility='hidden';ActivarBanner();",100);
		else
			setTimeout("document.getElementById('msgPantalla').style.visibility='hidden';",100);
	}
}

function desbloquearPagina(efecto,Banner){
	//alert("ddd");
	if(efecto==true)
		aclararPagina(0,Banner);
	else
		aclararPagina(13,Banner);
}


function PosicionXElemento(Elem){
	var curleft = 0;
	if (Elem.offsetParent)
	{
		while (Elem.offsetParent)
		{
			curleft += Elem.offsetLeft
			Elem = Elem.offsetParent;
		}
	}
	else if (Elem.x)
		curleft += Elem.x;
	return curleft;

}
function PosicionYElemento(Elem)
{
	var curtop = 0;
	if (Elem.offsetParent)
	{
		while (Elem.offsetParent)
		{
			curtop += Elem.offsetTop
			Elem = Elem.offsetParent;
		}
	}
	else if (Elem.y)
		curtop += Elem.y;
	return curtop;
}