Check documentation for the latest version of dhtmlxSuite onOpenStart DHTMLX Docs


fires at the moment when the "plus" icon is clicked in treegrid

boolean onOpenStart(string|number id,number state);
idstring|numberthe id of the related tree-item
statenumberthe current item state, 1 if item is currently opened
booleantrue - confirms opening/closing, false - denies opening/closing


treegrid.attachEvent("onOpenStart", function(){
  //custom code here
  return true;


Fires before real item opening, also fires for item closing.

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