js: Substantially simplify timer code

The C code in the Emscripten front-end already keeps a timer_active
variable to ensure that the timer can be activated only when it's
inactive, and deactivated only when it's active.  Adjusting the
JavaScript side to rely on this makes the code much simpler.  The only
oddity is that it now requests a new animation frame before calling the
callback so that it's ready to be cancelled if the callback decides to
deactivate the timer.

1 files changed, 1 insertions, 2 deletions

diff --git a/emccpre.js b/emccpre.js
index 16833f5..666d37d 100644
--- a/emccpre.js
+++ b/emccpre.js
@@ -90,8 +90,7 @@ var midpoint_test_str = "ABCDEFGHIKLMNOPRSTUVWXYZ0123456789";
 var midpoint_cache = [];
 
 // Variables used by js_activate_timer() and js_deactivate_timer().
-var timer = null;
-var timer_active = false;
+var timer;
 var timer_reference;
 
 // void timer_callback(double tplus);