javascript - How to continue Javascript function after Button click with Codebehind method is finished?

Question

Hello I have a javascript function which look like this:

function WebGrid1_OnAfterAdd(controlId) 
{      
    document.getElementById('TeilnehmerCounterButton').click()    
    var intern = document.getElementById('InterneTeilnehmer').value;
    var extern = document.getElementById('ExterneTeilnehmer').value;
    parent.parentTeilnehmer(intern, extern)
}

Only after the TeilnehmerCounterButton button with the codebehind method is finished it should load rest of the function.

how can i do this?

Thanks in advance for your help