function troca(foto){
	document.getElementById('fotog').src=foto;
}

function pagina(valor){
    http.open('GET','getFotos.php?v='+valor,true); 
	http.onreadystatechange=function(){
		if(http.readyState==4){
			document.getElementById('gals').innerHTML=http.responseText;
		}
	}
	http.send(null);
}

function getAjax(){
	ajax = null;
	try{
		ajax = new XMLHttpRequest();
		}catch(e){
			try{
				ajax = new ActiveXObject("Microsoft.XMLHttp");
			}catch(e){
				try{
					ajax = new ActiveXObject("MSXML2.XMLHttp");
				}catch(e){
					alert("Seu navegador não suporta Ajax");
				}
			}
	    }
	return ajax;
}

var http = getAjax();