function trocaFundo(){
	
	arrayFundo = new Array;	
	arrayFundo[0] = "imagens/FUNDOS/fundo_1.jpg";
	arrayFundo[1] = "imagens/FUNDOS/fundo_2.jpg";
	arrayFundo[2] = "imagens/FUNDOS/fundo_3.jpg";
	arrayFundo[3] = "imagens/FUNDOS/fundo_4.jpg";
	
	var bg = "";
	var pageURL = String(document.location);
	var bgUrl = pageURL.split("=");
	if (bgUrl[1]) { 
	bg = bgUrl[1]; 
	bgAtivo = bgUrl[1]; 
	}
	
	if (bg != "") {
		var meuBackground = arrayFundo[ parseInt(bg) ];
	}
	else
	{
		var randomico = "";
		randomico = Math.random() * arrayFundo.length;
		randomico = Math.floor(randomico);
		
		var meuBackground = arrayFundo[randomico];
		bgAtivo = randomico;

	}
	
	document.getElementById("base").style.backgroundImage = "url('" + meuBackground + "')";
	
}

function carrega(minhaUrl){
	location.href = minhaUrl + "?bg=" + bgAtivo;
}