Thread:Talk:ResourceLoader/Conditional script inclusion (e.g. if lt IE 9 )

My apologies if I failed to see some notes about conditional script inclusion but in a case a browser requires a pre-IE 9 script (add an additional JS script only for that particular situation), how is one to work around this problem with the ResourceLoader.

For example:

Register a separated module but it should only be loaded in case the necessary conditions are due to (pre-IE 9). $wgResourceModules['ext.srf.excanvas'] ...

Which method in the RL/JS could be used to load this module so that the condition  is met?