function openWindow(){
		var l = window.screen.width/2 - 650/2;
		var t = window.screen.height/2 -430/2;
		window.open('form_registro.php','registro','scrollbars=yes,width=676,height=590,left='+l+',top='+t+',screenX='+l+',screenY='+t+'')
	}
	
	function openLogin(){
		var l = window.screen.width/2 - 650/2;
		var t = window.screen.height/2 -430/2;
		window.open('login.php','login','scrollbars=yes,width=676,height=590,left='+l+',top='+t+',screenX='+l+',screenY='+t+'')
	}
	
	function openVideo(){
		var l = window.screen.width/2 - 650/2;
		var t = window.screen.height/2 -430/2;
		window.open('upload_video.php','video','scrollbars=yes,width=676,height=590,left='+l+',top='+t+',screenX='+l+',screenY='+t+'')
	}
	
	function openFoto(){
		var l = window.screen.width/2 - 650/2;
		var t = window.screen.height/2 -430/2;
		window.open('upload_foto.php','foto','scrollbars=yes,width=676,height=590,left='+l+',top='+t+',screenX='+l+',screenY='+t+'')
	}
	
	function openConcurso(idConcurso,tipo){
		var l = window.screen.width/2 - 650/2;
		var t = window.screen.height/2 -430/2;
		window.open('concurso.php?idConcurso='+idConcurso+'&tipo='+tipo,'concurso','scrollbars=yes,width=676,height=590,left='+l+',top='+t+',screenX='+l+',screenY='+t+'')
	}
	
	function openPremios(){
		var l = window.screen.width/2 - 650/2;
		var t = window.screen.height/2 -430/2;
		window.open('premios.php','premios','scrollbars=yes,width=676,height=590,left='+l+',top='+t+',screenX='+l+',screenY='+t+'')
	}
	
	function openErpeche(){
		/*
		var l = window.screen.width/2 - 650/2;
		var t = window.screen.height/2 -430/2;
		window.open('form_registro.htm','erpeche','width=100%,height=100%,left='+l+',top='+t+',screenX='+l+',screenY='+t+'')
		*/
		pagina = "erpeche.html";
		
		if (navigator.appName == "Microsoft Internet Explorer"){ // better be ie6 at least
			window.open(pagina, '', 'fullscreen=yes, scrollbars=auto, resizable=yes').focus();
		}
		else { // i.e. if Firefox
			window.open(pagina, '', 'width=' + (screen.width-5) + ',height=' + (screen.height-30) + ', scrollbars=auto, resizable=yes, ').focus();
		}
	}
	
	function preLoadImages(){
		preload_image_object = new Image();

     	image_url = new Array();
      	image_url[0] = 'images/bt_registrate.gif';
      	image_url[1] = 'images/bt_registrate_f2.gif';
      	image_url[2] = 'images/bt_foronline.gif';
      	image_url[3] = 'images/bt_foronline_f2.gif';
      	image_url[4] = 'images/bt_entrar.gif';
      	image_url[5] = 'images/bt_entrar_f2.gif';

       	var i = 0;
       	
       	for(i=0; i<=5; i++) 
        	preload_image_object.src = image_url[i];
	}