function valida (local)
    {
	    var localValidar = document.getElementById(local);
	    var formulario = localValidar.getElementsByTagName("input");

	    for (var i=0; i < formulario.length; i++)
	    {
	    	if (formulario[i].value == "")
	    	{
	    		var aux = formulario[i].name.toUpperCase();
	    		alert ("O campo " + aux + " deve ser preenchido");
	    		formulario[i].focus();
	    		return false;
	    	}
	    }
    	return true;
    }