Calling a catalog item variable onChange function programmatically

[lcbell]

I have written an onChange function for a catalog item variable. I was told that we need another control, Y, that will have the same behavior as the first control, X. I would normally move the code to a new function and put it after an onLoad function and then call the new function from the onChange functions. 
The onLoad script would look like:
   function onLoad() {
   }
   function myNewFunction(newValue) {
   }
The onChange script for control X would look like:
   function onChange (control, oldValue, newValue, isLoading) {
       myNewFunction(newValue);
   }
The onChange script for control Y would look like:
   function onChange (control, oldValue, newValue, isLoading) {
       myNewFunction( g_form.getValue('X') );
   }

I didn't want to mess with what to call myNewFunction and passing the argument from the onChange function to the new function but instead I just wanted to call the onChange function for control X from the onChange function for control Y. I looked at the code for the onChange function and saw that it was set by a function called variableOnChange. The argument for the variableOnChange function was the name of the control that started with "IO:" followed by the control sys_id. So in the onChange function for control Y I put the following code:
   var X = g_form.getControl('X');
   if(X && X.name) variableOnChange( X.name );

So now when the onChange function for control Y is called it also calls the onChange function for control X. Since I am using the OOB function variableOnChange, the arguments for the onChange function for control X come from control X.