JavaScript Error Logger

WHAT IT DOES

JavaScript Error Logger captures every JavaScript error and unhandled promise rejection that occurs on the page, displaying them in a clear, organized log. For each error, the tool shows the error type, message, stack trace, filename, line number, column number, and timestamp. You can filter errors by type (TypeError, ReferenceError, SyntaxError, RangeError, or Promise rejections), search through the log, copy individual errors or the entire log to your clipboard, and clear the log when needed. The log persists across page interactions, making it easy to track errors that happen early in the page lifecycle.

WHERE IT RUNS

The extension runs entirely within your browser's local environment using the BotGentz framework. All error capturing, parsing, and logging occur on your machine without any network requests. No error data, page content, or user activity is ever transmitted, uploaded, or stored externally. The tool works on any website and respects the browser's security boundaries, operating within the isolated extension sandbox. Errors are captured using native window event listeners.

HOW TO USE

Click the extension toolbar icon to open the JavaScript Error Logger panel. Errors are captured automatically as they occur and displayed in reverse chronological order (newest first). Each error entry shows the error type, message, location (filename and line number), and timestamp. Expand any entry to view the full stack trace. Use the filter dropdown to show only specific error types. Toggle "Show stack traces" to control whether stack traces are displayed. Toggle "Show timestamps" to show or hide timestamps. Enable "Auto open when errors occur" to automatically open the panel when an error is captured. Toggle "Clear on page navigation" to automatically clear the log when navigating to a new page. Adjust "Max errors to keep" to limit the number of stored errors. Click "Copy All Errors" to export the entire log, or use the "Copy" button on individual errors. Click "Clear Log" to remove all captured errors.

THE ERROR CAPTURE ENGINE — WHY IT WORKS

Most error logging tools rely on console interception or complex polyfills that miss many error types. This tool uses the browser's native event system to capture errors at the source: the window "error" event catches all uncaught JavaScript exceptions, providing access to the error message, filename, line number, column number, and the error object with its full stack trace. The "unhandledrejection" event captures promise rejections that aren't caught with .catch(), which are increasingly common in modern async code. Each captured error is normalized into a consistent format, with error type detection based on the error's constructor or message pattern. The stack trace is preserved in full but truncated for display to keep the log readable. The log is persisted using GM_setValue, so errors captured before the panel is opened are still available when you open it. This dual-event approach ensures comprehensive coverage of both synchronous and asynchronous error patterns.

THE PANEL

The JavaScript Error Logger panel is fully draggable by its title bar and remembers its position on screen per website. It snaps to the edges of your browser window for clean alignment. Collapse the panel to a compact icon strip using the minimize button, restoring it with a single click. Resize the panel by dragging any edge or corner; the error log and controls adjust proportionally. Press the Escape key to close the panel instantly. The panel maintains independent state for each browser tab, allowing you to monitor errors in multiple tabs simultaneously.

PLEASE NOTE

This extension requires the free BotGentz extension framework to be installed and enabled. Errors are captured via the standard window error events; errors that are caught and suppressed by the page's own error handlers will not appear in the log. The tool captures errors that occur after it is loaded; page initialization errors may be missed if they occur before the script runs. All error data is stored locally and is never transmitted, logged, or shared. The extension requests no network permissions and functions entirely offline. The source code is fully auditable and available for review.