Use your browser’s developer tools: start in the Console to see JavaScript messages and errors, then use the debugger to pause code, inspect values, and step through execution. If you are tracking a request triggered by a click, combine the Network panel with a breakpoint.
Start with the Console
The Console is the quickest place to look for page-script messages and errors, or to run a small expression in the current page context. In Chrome, open it with Command+Option+J on Mac, or Control+Shift+J on Windows, Linux, and ChromeOS. Shortcuts and menus can vary by browser version and platform. See Chrome’s DevTools overview.
In Firefox, the equivalent page-level panel is called the Web Console. Mozilla describes it as showing page-associated network requests, JavaScript, CSS and security errors and warnings, as well as messages logged by JavaScript running in the page context. See Mozilla’s Web Console guide.
- Open the page and its developer tools.
- Reload the page or repeat the action you are investigating.
- Look for errors, warnings, and logged messages. If useful, enter a small expression in the Console to inspect the current page context.
A Console error is evidence that something went wrong, but it may not show the sequence of code that led to it. For that, pause execution in the debugger.
Free tools Windows power users keep installed
One-click scans. No signup required.
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
- Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
Pause JavaScript and inspect what it is doing
In Chrome, open the Sources panel, find a relevant script, and set a breakpoint on a line. Reproduce the action that runs the code. When execution pauses, inspect the current function’s values and step through its execution. You can also query values in the Console while paused. Chrome’s JavaScript debugging guide covers breakpoints, stepping, and inspecting values; stepping can still be useful when code is minified.
- Open Sources in DevTools.
- Navigate to a script that appears related to the behavior. Use the debugger’s source navigation or filtering if the page has many scripts.
- Click a line number to set a breakpoint.
- Repeat the page action. If execution pauses, inspect the current values and use the stepping controls to follow what runs next.
If the breakpoint is not reached, the selected line may not run for that action. Choose a different relevant line or use the Console and Network panel to narrow down what is happening.
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
Trace a request caused by a page action
If clicking a button sends an unexpected request, inspect the request in the Network panel, then use a breakpoint to find the AJAX or Fetch code that initiated it. This connects the visible network activity to the JavaScript execution that triggered it. See Chrome’s Network reference and its debugging guide.
- Use the Network panel when the question is what request was sent.
- Use a debugger breakpoint when the question is which code path initiated it or what values it used.
Choose the view that answers your question
| What you need to find out | Where to look |
|---|---|
| What errors, warnings, or messages did the page produce? | Console (Chrome) or Web Console (Firefox) |
| Which code ran, and what values did it use? | Sources debugger and a breakpoint |
| Which code caused an unexpected request? | Network panel plus a debugger breakpoint |
Common snags
- You see an error but cannot tell what caused it: set a breakpoint in the relevant script, reproduce the action, and inspect execution while paused.
- The page has many scripts or minified code: use the debugger’s source navigation and filtering where available, then set a breakpoint on a relevant line. Debugger stepping can work with minified code.
- You are looking for the wrong panel: Chrome calls its debugger panel Sources; Firefox calls its page-level log panel the Web Console. Names and interfaces differ across browsers.
- A shortcut does not open the Console: confirm your browser and operating system, or open developer tools from the browser’s developer tools menu; shortcuts may vary.
- You need Safari or Edge-specific steps: the browser documentation cited here establishes Chrome and Firefox workflows, not current Safari or Edge instructions. Check the relevant browser’s official documentation for its exact panel names and shortcuts.
Or skip the browser setup
If your goal is to capture how a page looks rather than inspect its live JavaScript execution, ScreenshotNeo can return a page screenshot or PDF from one GET request. For example, save a WebP capture of Stripe like this:
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
curl -G "https://api.screenshotneo.com/v1/shot" -d access_key=YOUR_API_KEY --data-urlencode url=https://stripe.com -o shot.webpSee the ScreenshotNeo documentation for request options. It removes cookie banners, newsletter popups, and chat widgets before capture; bot checks, blank pages, and failed loads are not billed; its MCP server lets AI agents take screenshots; and the Free plan includes 1,000 screenshots a month without a card, with paid plans starting at $5 for 3,000. This is for capturing a page, not stepping through its JavaScript.
Sign up free for 1,000 screenshots a month with no card.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Frequently Asked Questions
Can I see JavaScript errors without changing the website?
Yes. Open the browser’s developer tools and check the Console in Chrome or Web Console in Firefox; these panels show page-associated messages and errors.
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
How do I find which code runs when I click a button?
Set a breakpoint in a relevant script in the debugger, click the button, and inspect execution when it pauses.
Quick Recap
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
