Troubleshoot JavaScript errors

JavaScript errors can interfere with essential WooCommerce functions like product displays, checkout, and form submissions. This guide shows you where to find these errors and how to troubleshoot them.

Note: This document is meant to serve as a helpful guide for advanced troubleshooting; however, the procedures described are beyond the scope of our support policy and we cannot provide direct assistance with implementing them. 

If you would like to seek assistance from a qualified WordPress/WooCommerce developer, we highly recommend Codeable or a Woo Agency Partner. 

JavaScript is a programming language that runs directly in the browser, not on the server. This allows it to respond quickly to user actions — like adding a product to the cart or updating quantities — without needing to reload the entire page. 

A single JavaScript error can interrupt these functions and impact other features on the same page. Understanding JavaScript’s role in your site can help you identify and resolve these errors effectively.

In WooCommerce, JavaScript plays a key role in enhancing functionality on your site. Here are some common areas where JavaScript is used:

• Cart and checkout pages: JavaScript automatically updates shipping methods and costs when a customer changes their shipping address.
• Payment methods on checkout: It loads the correct payment options based on the customer’s billing address.
• Variable product pages: JavaScript loads variation images and stock availability when customers choose product variations.
• Add to cart buttons: Allows customers to add products directly to their cart from shop and category pages using AJAX, so the page doesn’t reload.
• WP-Admin product management: JavaScript powers product tabs, variation lists, and search boxes for products and categories.

If these elements aren’t working correctly — such as a spinner loading indefinitely or images not updating — a JavaScript error is likely to be causing the issue.

You can use the built-in developer tools in most browsers to find JavasScript errors. Here’s a quick overview of how to access these tools in Chrome, Safari, and Firefox on both MacOS and Windows.

1. MacOS and Windows: Open your WooCommerce site in Chrome.
2. Right-click on the page and select Inspect or press Cmd+Option+J (Mac) or Ctrl+Shift+J (Windows) to open the Console.
3. Look for any error messages in red in Console. These messages highlight JavaScript errors that may affect site functionality.

1. MacOS only (Developer Tools are not available on Windows): Open your WooCommerce site in Safari.
2. First, enable the Develop menu via Safari > Settings. Under the Advanced tab, check the Show features for web developers box.
3. Open the Console by going to Develop > Show JavaScript Console or pressing Cmd+Option+C.
4. Look for errors in red, which indicate JavaScript issues.

1. MacOS and Windows: Open your WooCommerce site in Firefox.
2. Right-click on the page and select Inspect or press Cmd+Option+K (Mac) or Ctrl+Shift+K (Windows) to open the Console.
3. Any JavaScript errors will appear in red text, showing where issues may be occurring on your site.

Using these tools, you can identify JavaScript errors and start troubleshooting effectively. 

Here’s what to look for:

• GET or POST messages: These messages indicate that something hasn’t loaded correctly from the server, like when order details don’t update or an image link is broken. While they’re usually just alerts about missing assets, they can be hidden in Console Settings > Hide Network if they aren’t causing a visible issue.
• White and yellow messages: These are typically HTTPS warnings or debug messages, which are mostly harmless and don’t affect site functionality.
• Red errors (excluding GET or POST): These messages point to actual JavaScript errors that can disrupt features on your WooCommerce site. Focus on these red error messages, as they are most likely causing functionality issues.

JavaScript errors come in several types, with SyntaxError being the most disruptive:

• SyntaxError: This error means the browser can’t read the JavaScript code structure at all, preventing it from interpreting any JavaScript on the page. A SyntaxError in one extension or plugin can even break JavaScript loaded via unrelated plugins or themes, affecting your entire site’s functionality.
• Other JavaScript Errors: Errors that aren’t SyntaxErrors may only affect the specific part of the code where they occur. However, these errors often have a ripple effect, breaking other JavaScript features on the page as well.

Whenever you see an error, first check the message to understand what’s causing it. A quick search can often help you identify the issue’s source and possible solutions.

Often, the error message will display a filename in the top-right corner. Hover over this filename to see the file’s full path, or right-click and select Copy link address to view the URL.

For example:

If the file path shows https://woostore.mystagingwebsite.com/wp-content/plugins/woocommerce-subscriptions/assets/js/variable.min.js?ver=4.9.5, this file likely belongs to the WooCommerce Subscriptions extension. If you encounter an error here, try disabling this extension before performing a full conflict test.

Errors related to filenames usually mean there’s either broken code in the extension/plugin or a conflict between different versions of a JavaScript library. 

In some cases, the error message itself provides useful information about the issue. For example, a message from a payment gateway may indicate that a country is not supported. Adjusting the country settings in your site’s WP Admin dashboard via WooCommerce > General Settings might resolve such errors without needing to disable the extension/plugin.

Occasionally, the error won’t specify a particular extension/plugin but will reference general files like index or cache.

In these cases, try the following:

1. Disable caching and optimization plugins: Caching plugins often interfere with JavaScript dependencies, so temporarily disabling them can help identify if they’re causing the error.
2. Perform a full conflict test: If the issue persists, disable all extensions and plugins (except WooCommerce) and switch to a default theme to see if the error remains.
3. Check text widgets for JavaScript: Occasionally, custom JavaScript added to text widgets can cause errors. Review these widgets to ensure they’re not introducing issues.

These steps can help isolate and resolve the source of JavaScript errors in your WooCommerce site.

Do you still have questions and need assistance? 

• Get in touch with a Happiness Engineer via our Help Desk. We provide support for extensions developed by and/or sold on WooCommerce.com, and Jetpack/WordPress.com customers.
• If you are not a customer, we recommend finding help in the WooCommerce support forum or hiring a Woo Agency Partner. These are trusted agencies with a proven track record of building highly customized, scalable online stores. Learn more about Woo Agency Partners.