Countdown Timer Injector

WHAT IT DOES

This script injects a fully customizable countdown timer into any webpage you visit. Set a target date and time, give it a label, and the timer will count down in real-time with a visual progress bar. When the countdown completes, you can choose to receive a browser alert, open a URL automatically, or get a desktop notification. The timer remembers its settings across page reloads and even across different websites, so you can keep track of important deadlines without leaving your current tab. Whether you're waiting for a product launch, a meeting, a livestream, or a deadline, this tool puts a countdown right where you need it—on the page you're already looking at.

WHERE IT RUNS

This script works on every website—from email inboxes to social media feeds, project management dashboards to documentation pages. It runs where you need it, without requiring a separate app or tab. The timer panel floats above the page content and stays accessible while you browse. All settings are stored locally in your browser using GM_setValue, so your countdowns persist across page reloads and browser sessions.

HOW TO USE

Once installed, the timer panel appears as a floating widget on every page. Click the panel to expand it and configure your countdown: enter a target date and time, give it a label (e.g., "Launch"), choose what happens when the timer completes, and toggle auto-start. The timer will begin counting down immediately. You can pause, reset, or clear the timer at any time. The panel is draggable and remembers its position per site. If you minimize the panel, a small icon remains visible so you can quickly check the remaining time.

TECHNICAL MECHANISM

The timer calculates remaining time by continuously comparing the current system time against the stored target date, updating the display every 200 milliseconds. The progress bar reflects the percentage of time elapsed between the countdown start and the target. The entire state—target date, label, completion action, URL, and panel position—is persisted using GM_setValue, ensuring zero data loss on navigation. The timer runs inside a single-page environment; page navigation does not reset it because settings are loaded from storage on each page load. This approach avoids relying on external servers or cloud sync, keeping everything local and instant.

THE PANEL

The panel is a floating overlay that can be dragged to any position on the page. Its position is remembered per website (not globally), so you can place it where it works best for each domain—top-right on one site, bottom-left on another. The panel can be collapsed to a small icon using the minimize button, and expanded again when you need to adjust settings. Panel resizing is not required as the layout adapts to its content. The panel respects the Escape key: pressing Escape closes the panel if it is expanded, returning it to its collapsed state.

PLEASE NOTE

This script requires the free BotGentz extension to run. Websites change over time, and scripts may need occasional updates to maintain compatibility. All timer data is stored locally in your browser using GM_setValue—no data is sent to any server. The script does not track your browsing history or read any personal data. When the timer completes and the action is "open URL", the URL will be opened in a new tab; ensure you only use trusted URLs.