How to deal with nested functions in javascript?

It might be a beginner question but I'm facing with the next situation:

$(function f() {

  function test2() {
    //.....
  }

  function GetData() {
    //.....
  }    
  function update() {
    test2();
    GetData();
    //...
  }//end update

  update();

});//end f()

function stop() {
  clearInterval(multipleCalls);
}

function start() {
  multipleCalls=null; //this is a global variable
  setTimeout(update, 1000);
}

The stop function stops a graphic when a button is pressed and everything works fine. The start function should restart a graphic when a button is pressed. My guess is that the update function is not well invoked in start function. How could I do so everything to work fine?

Solution

You have currently commented out the } that closes the update function, so the line that says end f doesn't in fact end f(). In its present state, your code would not execute. (I note that someone else edited your code after which this remark is no longer valid; I don't know if the edit is closer to your actual code, or if it did in fact obscure a real error)
You're referring to both multiplecalls and multipleCalls. Note that javascript is case sensitive.
You're clearing multipleCalls but never setting it to anything but null. Did you intend to write multipleCalls = setTimeout(update, 1000) ?
start, being placed outside of f, won't have access to update. Either define update and the functions it is dependent upon outside of f(), or make it globally accessible, i.e.
```
window.update = function() { ... }
```
Which you'd then be able to access as setTimeout(window.update, 1000);