function is_valid_form( form_object, fields_needed_list, alert_msg ){
	fields_needed_list = ( typeof( fields_needed_list ) == 'string' ) ? fields_needed_list.split( ',' ) : fields_needed_list;
	for( i = 0; i<fields_needed_list.length; i++ ){
		if( form_object.elements[fields_needed_list[i]] != null && ( form_object.elements[fields_needed_list[i]].value == "" || form_object.elements[fields_needed_list[i]].value == null ) ){
			alert(alert_msg);
			form_object.elements[fields_needed_list[i]].focus();	
			return false;
		}
	}
	return true;
}
function valida_email(campo) {
	if (campo.value != "") {
		if (!(/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(campo.value))) { 
			alert("Favor informar um e-mail válido.") 
			campo.focus() ;
			return false;
		} else {
			return true;
		}
	}
}