How to Fix a Web Game Breaking When the Tab Is Backgrounded

A web game that jumps or breaks after you switch tabs is reacting to a huge accumulated time step from background throttling. Clamping delta and pausing on hidden fixes it. Here is how.

How to fix it

1. Clamp delta time

Cap the delta you feed the simulation to a sensible maximum (say one or two frames' worth). A backgrounded tab can return a delta of many seconds, which makes physics and movement explode.

2. Pause on visibilitychange

Listen for the visibilitychange event; when document.hidden is true, pause the loop and audio. This avoids accumulating a giant time gap and saves CPU while hidden.

3. Resume cleanly

On returning to visible, reset the timer baseline so the first frame uses a normal delta, then resume. This prevents the lurch that comes from treating the away time as one frame.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every HTML5 error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.