function validaForm(form){
	for (i=0;i<form.length;i++){
		var obg = form[i].name.indexOf("x");
		if (obg!=-1){
			if (form[i].value == ""){
				var nome = form[i].name.substring(1,form[i].name.length);
				alert("Preecha o campo " + nome + ".")
				form[i].focus();
				return false;
			}
		} 
	} 
	return true;
}