Javascript API for listbox selected text

[#1]

Hello,

I have a JS to select the lang selected in QVW listbox. I fetch the lang code from the browser and want to overwrite the list box selection.

var thisDoc = Qv.GetCurrentDocument();

var langBox = thisDoc.GetObject("LANG", function(){});

console.log(langBox.Data.Rows.length); -->ES as I set language to spanish

  (function(){

      console.log('no selection, use browser')

      langBox.Data.ClearSelections();

      setTimeout(langBox.Data.SelectTexts(langCode),10);   

})();

I get an error that ClearSelections and SelectTexts are undefined functions. Can you suggest me which API to use to do the job?

Thanks

DV

[#2]

Anyone has any suggestions on where to look for help?

[#3]

I checked JsDoc Reference - Getting Started

and I do see that ClearSelections and SelectTexts are valid functions. But I do not find these in my QVAjax. I get function undefined error too.