Javascript generated by s:doubleselect has global variables that can interfer with the rest of the app

In the JavaScript code generated by the s:doubleselect tag (and, possibly other tags), there are for loops using the following format :

for (m = ObservationForm_observation_countryKeyTemp.options.length - 1; m >= 0; m--) {
            ObservationForm_observation_countryKeyTemp.options[m] = null; 

The variable m is never defined before that. So this creates a globally scoped m variable that can interfere with other JavaScript code.

In my case it interfered with library code that is processed with a minifyer (I think in this case it is Google Closure Compiler) and contains a lot of one-letter variable name, such as... m.

So I got the following error :

Uncaught TypeError: number is not a function

Which was difficult to trace since the code was minified. If the code was not minified, then the error did not happen any more.

I believe it would be enough to just use the var keyword in the loop definition to remove this problem :

for (var m = ObservationForm_observation_countryKeyTemp.options.length - 1; m >= 0; m--) {
            ObservationForm_observation_countryKeyTemp.options[m] = null;