var funcion_popupWindow=null; 
function funcion_popup(mi_pagina,mi_nombre,w,h,pos,infocus,parametros)
{ 
	if(pos == 'random')
	{ 
		LeftPosition = (screen.width)?Math.floor(Math.random()*(screen.width-w)):100; 
		TopPosition = (screen.height)?Math.floor(Math.random()*((screen.height-h)-75)):100;
	} 
	
	if(pos =='center')
	{ 
		LeftPosition = (screen.width)?(screen.width-w)/2:100; 
		TopPosition = (screen.height)?(screen.height-h)/2:100;
	} 
	
	else if((pos != 'center' && pos != 'random') || pos == null)
	{
		LeftPosition=100;
		TopPosition=100;
	}

		
	/*settings='width='+ w + ',height='+ h + ',top=' + TopPosition + ',left=' + LeftPosition + ',location=no,directories=no,menubar=no,toolbar=no,status=no,scrollbars=no,resizable=no,dependent=no';*/

	if (parametros == 'default') parametros='location=no,directories=no,menubar=no,toolbar=no,status=no,scrollbars=no,resizable=no,dependent=no';

	settings='width='+ w + ',height='+ h + ',top=' + TopPosition + ',left=' + LeftPosition	+ ',' + parametros;
		
	funcion_popupWindow = window.open('',mi_nombre,settings); 
	
	if(infocus == 'front')
	{
		funcion_popupWindow.focus();
		funcion_popupWindow.location = mi_pagina;
	} 
}