Technical Guide
Browser wake lock sounds simple, but it is deliberately limited. The API is designed to keep a visible screen awake temporarily, not to override every power policy on every device.
When a page asks for a screen wake lock, the browser is not promising to keep the display awake forever. It is granting a temporary request that can still be limited by the operating system, low-power behavior, background-tab rules, or the browser's own safety checks.
That is why NoSleepScreen uses a visible timer and status area instead of pretending the tool has full control over the device.
Browsers tend to allow sensitive actions only after user intent is clear. Starting wake lock from a button press is one of the cleanest ways to show that intent. If a site tried to activate wake lock automatically without a user action, many browsers would reject it.
Wake lock is usually tied to the browsing context that is currently active and visible. If the user switches tabs, minimizes the browser, locks the device, or puts the page in the background, the browser may release the lock. This is normal behavior and one of the most common reasons people think the tool is broken when it is actually following platform rules.
A wake-lock request should run on a secure origin such as HTTPS or localhost. This protects users and gives browsers a safer environment for advanced APIs. If the page is opened from an insecure origin, a wake-lock request may fail immediately before the session ever starts.