Timing Problem when Sending an Ajax Request inside a custom validator

[fes]

I wanted to create a custom Validator, that sends an ajax-request. After some validation on the server, the right case should be returned. The problem is, that the ajax-request needs a moment to answer, so that the return is excecuted before the variable could be set. Is there any way, I can avoid or solve this problem.

    
isc.Validator.addValidator(
    "serversideValidator", 
    function (item,validator,value) {
        var validator_return = null;
        isc.RPCManager.sendRequest({
            httpMethod: "GET",
            useSimpleHttp: true,
            evalResult: false,
            actionURL:"/ajax/read/2/validator/" + item.name + "/" + value ,
            callback:
                function (rpcResponse, data, rpcRequest) {
                    validator_return = false;
                    if (data == 'true'){
                        validator_return = true;
                    }
                },
        });
        if (validator_return!=null){
            return validator_return;
        }
    }
);

[Isomorphic]

Use a type:serverCustom Validator. Examples are in the Feature Explorer under Server Examples -> Validation.

[fes]

I forgot to say, that i am only using the Rest-Api of Smartclient with JavaScript and JSON and neither Java nor XML.

[didierv]

In that situation, we do not declare a validator on the client side. When a REST add or update is sent to the server, if the record is not valid, we send back a JSON response with status -4 (STATUS_VALIDATION_ERROR), and the error messages. You'll find a JSON example with error messages in the RestDatasource documentation.

[fes]

Thank you for your help so far.
Now I just need to know, how I can arrange it, that a certain field is recognized as wrong and gets the flag beneath it. How can I do that?