How to Track JavaScript Errors on Your Website with statpx

JavaScript errors are silent killers. A broken script on your checkout page, a failed API call on your sign-up form, an unhandled promise rejection in your navigation menu — your users hit them and leave, and you never know why.

Traditional monitoring tools like Sentry are powerful but require significant setup, ongoing maintenance, and often carry a cost. statpx takes a different approach: JS error tracking is built in, automatic, and requires zero configuration.

How statpx Captures JavaScript Errors

The moment you install the statpx tracking snippet, it starts listening for two browser events:

• window.onerror — captures standard JavaScript errors: uncaught exceptions, syntax errors, type errors, and more
• window.onunhandledrejection — captures unhandled Promise rejections, which are increasingly common in modern async JavaScript code

When either event fires, statpx records the error message, the source file, the line number, and the page where it happened — all in real-time, from real users' browsers. No sampling, no synthetic tests, no separate SDK to install.

Viewing Your JS Errors Dashboard

In your statpx dashboard, navigate to any site and click JS Errors in the left sidebar. The dashboard shows:

• Total Errors — how many error events were captured in the selected period
• Unique Error Types — distinct error messages (helps you prioritize)
• Affected Pages — how many different URLs had at least one error
• Error Rate — errors per pageview, color-coded as clean / low / high

The Top Errors table groups errors by message, shows how many sessions were affected, how many pages had the error, and when it was last seen. This lets you instantly spot which errors are widespread versus one-offs.

Error Rate: What's Normal?

A small amount of JS errors is unavoidable — browser extensions inject scripts, ad blockers modify the DOM, and older browsers behave unexpectedly. As a general benchmark:

• Under 0.5% — healthy. Mostly extension-related noise.
• 0.5%–2% — worth investigating. Likely a real issue affecting some users.
• Over 2% — take action now. A significant portion of your users are experiencing broken functionality.

statpx color-codes the error rate badge (green / amber / red) so you can tell at a glance whether you need to act.

Finding the Pages That Matter Most

The Pages with Errors table shows which URLs generate the most errors. Sort by error count to find your worst-performing pages. A high error count on /checkout or /signup is far more damaging than errors on a rarely visited blog post.

Once you identify the page, use the Recent Error Log at the bottom of the dashboard to see individual events — including the error message, source file, and line number. Cross-reference this with your JavaScript source maps to locate the exact code causing the problem.

Types of Errors statpx Captures

Standard JavaScript Errors (window.onerror)

These are the classic runtime errors: TypeError: Cannot read properties of undefined, ReferenceError: x is not defined, failed script loads, and syntax errors in dynamically evaluated code. Each appears in statpx tagged as Error type.

Unhandled Promise Rejections

Modern JavaScript relies heavily on async/await and Promises. When a Promise rejects without a .catch() handler, the browser fires an unhandledrejection event. These are particularly sneaky — they don't always show up in browser consoles for end users. statpx captures them and tags them as Promise type in your dashboard.

Privacy and Performance

statpx only captures the error message, file, and line number — never the values of local variables, user input, or any PII. The error payload is tiny (under 500 bytes) and sent asynchronously, so it has no measurable impact on your site's performance or Core Web Vitals.

The Bottom Line

JavaScript errors in production are almost always invisible until a user complains — or until you notice a conversion drop. statpx makes them visible automatically, without any additional setup, SDKs, or ongoing cost.

Check your JS Errors dashboard today. If you already have statpx installed, the data is already there. You might be surprised by what's been silently breaking.