Conversation
supportHello, I’m experiencing a JavaScript error that breaks my event tracking. When users click a WhatsApp button on my site, the console logs: Uncaught TypeError: Cannot read properties of undefined (reading 'toString') at e (pixel-cat.min.js?ver=3.2.0:1:3688) at HTMLAnchorElement.<anonymous> (pixel-cat.min.js?ver=3.2.0:1:6214) at HTMLAnchorElement.dispatch (jquery.min.js?ver=3.7.1:2:40035) at v.handle (jquery.min.js?ver=3.7.1:2:38006) The affected file is: /wp-content/plugins/facebook-conversion-pixel/pixel-cat.min.js?ver=3.2.0 The error happens when Pixel Cat is tracking a Click event on an Elementor button linking to WhatsApp (e.g. https://api.whatsapp.com/send?phone=333XXXXX ). The <a> element looks like this: <a class="elementor-button-link track-wa" href="https://api.whatsapp.com/send?phone=333XXXXX" target="_blank"> <span class="elementor-button-text">Scrivici su WhatsApp</span> </a> Everything worked fine until a few days ago. Now, clicking the button triggers this error, and the event is not sent to Google Analytics. It seems the script is trying to call .toString() on an undefined variable — possibly when trying to read the link text or label. Thanks
Hi Andrea, Thanks for the detailed report. Before I ask a developer to dig into this, can you try two quick isolation tests so we know where the break is happening? Test A — Remove custom class on the existing button Temporarily remove the track-wa CSS class from the current WhatsApp button and Pixel Cat event and test again. If the error disappears when the class is removed, that tells us the issue is likely coming from the selector/event configuration tied to that class. Test B — Create a fresh test button & event On a draft or hidden page, add a brand-new WhatsApp button without the track-wa class. Then create a new Pixel Cat event to track that button (use a different selector) and test it. If the new button tracks without errors, it means the issue is specific to the original implementation rather than WhatsApp links in general. Once you run those two tests, let me know the results. If the problem persists, please also send: A link to a page where the issue can be seen Screenshots of how the event is set up in Pixel Cat (the configuration screen) Any steps required to reproduce it That will let us reproduce it accurately and look deeper. All the best.
Hi, Thanks for your reply and for outlining those tests. Here are the results: Test A Removing the custom class I removed the custom class and deleted the related event from PixelCat. No errors appeared in the console. Test B New button & new event I created a brand-new button and GA event using a different class name and the “click on element” trigger. When clicking the new button, the same error still appears in the console: pixel-cat.min.js?ver=3.2.0:1 Uncaught TypeError: Cannot read properties of undefined (reading 'toString') at e (pixel-cat.min.js?ver=3.2.0:1:3688) at HTMLDivElement.<anonymous> (pixel-cat.min.js?ver=3.2.0:1:6214) at HTMLDivElement.dispatch (jquery.min.js?ver=3.7.1:2:40035) at v.handle (jquery.min.js?ver=3.7.1:2:38006) I also tried: Excluding pixel-cat.min.js and pixel-cat.js from WP Rocket’s minify and defer settings Excluding the .whatsapp-btn class from CSS minification Fully deactivating WP Rocket The error still occurs. What’s strange is that I have the same issue on two different websites , both use WP Rocket, WooCommerce, FunnelKit, and Wordfence (Learning Mode). The main problem is that GA events are not being sent , and nothing appears in Tag Assistant . This behavior started around two weeks ago , before that, everything worked fine. Can I send you screens and other details in private? Thanks, Andrea
I found the cause of the issue: it was a manually inserted TikTok Pixel snippet that was interfering with PixelCat’s event tracking. After removing that snippet, everything is working correctly again: no console errors, and GA events are being tracked as expected. EDIT A quick update on the issue — I’ve tested different ways to integrate the TikTok Pixel, both manually and through plugins like FunnelKit. In every case, as soon as the TikTok Pixel script is added, the same PixelCat JavaScript error reappears. This basically prevents me from using TikTok tracking unless I upgrade to the PixelCat premium version, which I’d prefer to avoid if possible. I also noticed that in your latest update (version 3.2.0), you introduced support for TikTok’s API. Could it be that this new implementation is somehow related to the error or causing a conflict when a TikTok Pixel script is already present on the site? This reply was modified 7 months ago by ANDCAP .
Hi Andrea, Thanks so much for digging into this and sharing what you found. You may have identified the root cause of the issue with the TikTok Pixel snippet. We tried briefly to replicate the error on our side but weren’t able to, so it’s possible we missed a step. Could you share the exact steps you followed to reproduce the error? Knowing the precise workflow will help us replicate it accurately and speed up investigating a fix. Screenshots or a short recording of the steps would be perfect, if possible. Really appreciate your help on this. All the best.
I sent you the video link via the contact form on your website at https://fatcatapps.com . This reply was modified 6 months, 3 weeks ago by ANDCAP .
Hi Andrea, Thanks for sending that over. I’ve watched the video and can clearly see the issue now. I’ve passed this on to our developer to investigate further. We’ll follow up with you as soon as we have more information. All the best.
Hi Andrea, I hope you are doing well. I just wanted to follow up on this thread. Since we last spoke, we’ve made a number of updates to Pixel Cat, including some changes around how tracking scripts interact with other pixels. Could you let me know if you’re still experiencing this issue when the TikTok Pixel is present on your site? If it’s still happening, feel free to send over the page URL again and I can take another look. If it’s no longer occurring, that would also be helpful to know so we can confirm whether one of the recent updates resolved it. All the best.
Hi Andrea, Thanks for the detailed report. Before I ask a developer to dig into this, can you try two quick isolation tests so we know where the break is happening? Test A — Remove custom class on the existing button Temporarily remove the track-wa CSS class from the current WhatsApp button and Pixel Cat event and test again. If the error disappears when the class is removed, that tells us the issue is likely coming from the selector/event configuration tied to that class. Test B — Create a fresh test button & event On a draft or hidden page, add a brand-new WhatsApp button without the track-wa class. Then create a new Pixel Cat event to track that button (use a different selector) and test it. If the new button tracks without errors, it means the issue is specific to the original implementation rather than WhatsApp links in general. Once you run those two tests, let me know the results. If the problem persists, please also send: A link to a page where the issue can be seen Screenshots of how the event is set up in Pixel Cat (the configuration screen) Any steps required to reproduce it That will let us reproduce it accurately and look deeper. All the best.
Hi, Thanks for your reply and for outlining those tests. Here are the results: Test A Removing the custom class I removed the custom class and deleted the related event from PixelCat. No errors appeared in the console. Test B New button & new event I created a brand-new button and GA event using a different class name and the “click on element” trigger. When clicking the new button, the same error still appears in the console: pixel-cat.min.js?ver=3.2.0:1 Uncaught TypeError: Cannot read properties of undefined (reading 'toString') at e (pixel-cat.min.js?ver=3.2.0:1:3688) at HTMLDivElement.<anonymous> (pixel-cat.min.js?ver=3.2.0:1:6214) at HTMLDivElement.dispatch (jquery.min.js?ver=3.7.1:2:40035) at v.handle (jquery.min.js?ver=3.7.1:2:38006) I also tried: Excluding pixel-cat.min.js and pixel-cat.js from WP Rocket’s minify and defer settings Excluding the .whatsapp-btn class from CSS minification Fully deactivating WP Rocket The error still occurs. What’s strange is that I have the same issue on two different websites , both use WP Rocket, WooCommerce, FunnelKit, and Wordfence (Learning Mode). The main problem is that GA events are not being sent , and nothing appears in Tag Assistant . This behavior started around two weeks ago , before that, everything worked fine. Can I send you screens and other details in private? Thanks, Andrea
I found the cause of the issue: it was a manually inserted TikTok Pixel snippet that was interfering with PixelCat’s event tracking. After removing that snippet, everything is working correctly again: no console errors, and GA events are being tracked as expected. EDIT A quick update on the issue — I’ve tested different ways to integrate the TikTok Pixel, both manually and through plugins like FunnelKit. In every case, as soon as the TikTok Pixel script is added, the same PixelCat JavaScript error reappears. This basically prevents me from using TikTok tracking unless I upgrade to the PixelCat premium version, which I’d prefer to avoid if possible. I also noticed that in your latest update (version 3.2.0), you introduced support for TikTok’s API. Could it be that this new implementation is somehow related to the error or causing a conflict when a TikTok Pixel script is already present on the site? This reply was modified 7 months ago by ANDCAP .
Hi Andrea, Thanks so much for digging into this and sharing what you found. You may have identified the root cause of the issue with the TikTok Pixel snippet. We tried briefly to replicate the error on our side but weren’t able to, so it’s possible we missed a step. Could you share the exact steps you followed to reproduce the error? Knowing the precise workflow will help us replicate it accurately and speed up investigating a fix. Screenshots or a short recording of the steps would be perfect, if possible. Really appreciate your help on this. All the best.
I sent you the video link via the contact form on your website at https://fatcatapps.com . This reply was modified 6 months, 3 weeks ago by ANDCAP .
Hi Andrea, Thanks for sending that over. I’ve watched the video and can clearly see the issue now. I’ve passed this on to our developer to investigate further. We’ll follow up with you as soon as we have more information. All the best.
Hi Andrea, I hope you are doing well. I just wanted to follow up on this thread. Since we last spoke, we’ve made a number of updates to Pixel Cat, including some changes around how tracking scripts interact with other pixels. Could you let me know if you’re still experiencing this issue when the TikTok Pixel is present on your site? If it’s still happening, feel free to send over the page URL again and I can take another look. If it’s no longer occurring, that would also be helpful to know so we can confirm whether one of the recent updates resolved it. All the best.