1 files changed, 6 insertions, 4 deletions
diff --git a/components/script/timers.rs b/components/script/timers.rs
index 14c4eb89c13..b86bdc17aae 100644
--- a/components/script/timers.rs
+++ b/components/script/timers.rs
@@ -228,18 +228,20 @@ impl OneshotTimers {
     }
 
     pub fn suspend(&self) {
-        assert!(self.suspended_since.get().is_none());
+        // Suspend is idempotent: do nothing if the timers are already suspended.
+        if self.suspended_since.get().is_some() {
+            return warn!("Suspending an already suspended timer.");
+        }
 
         self.suspended_since.set(Some(precise_time_ms()));
         self.invalidate_expected_event_id();
     }
 
     pub fn resume(&self) {
-        assert!(self.suspended_since.get().is_some());
-
+        // Suspend is idempotent: do nothing if the timers are already suspended.
         let additional_offset = match self.suspended_since.get() {
             Some(suspended_since) => precise_time_ms() - suspended_since,
-            None => panic!("Timers are not suspended.")
+            None => return warn!("Resuming an already resumed timer."),
         };
 
         self.suspension_offset.set(self.suspension_offset.get() + additional_offset);