Why doesn't selected variant change the product photo but other times it does?

Technical Q&A

Topic summary

A Shopify theme is experiencing intermittent issues where selecting product variants doesn’t update the product photo. The problem occurs inconsistently—sometimes working after a page reload, sometimes not.

Root Cause Identified:

  • JavaScript error in the resetProductFormState function
  • Console shows: Uncaught TypeError: productForm?.toggleSubmitButton is not a function
  • Likely a timing issue where the script runs before productForm is fully initialized

Proposed Solution:

  • Commenting out the problematic function appears to resolve the variant photo switching issue
  • The function’s original purpose was likely to prevent rapid clicking on the “Add to cart” button
  • After removal, the site functions normally, though rapid button clicking behavior may change

Status: The workaround (commenting out the function) seems viable, but the underlying initialization timing issue remains unaddressed.

Summarized with AI on October 31. AI used: claude-sonnet-4-5-20250929.
1

I can’t figure this out. When I load the page there is a chance that product photos with variants won’t work, then I reload the page and then they work, but customer won’t be reloading the page to see if it works. Sometimes it doesn’t work even after reloading.

2

Hi, share your URL, please.

3

https://pawnap.store/products/glow-stitch

4

there is a problem with the resetProductFormState function in your JS file.

resetProductFormState() {
  const productForm = this.productForm;
  productForm?.toggleSubmitButton(true);
  productForm?.handleErrorMessage();
}

You can see in the console:

Uncaught TypeError: productForm?.toggleSubmitButton is not a function

If the issue disappears after a page reload, it suggests a timing issue - your script might be running before productForm is properly initialized.

5

What function does it serve? I commented it out and now it seems to be working. Can I live without it?

6

I think it can prevent fast clicking on the Add to cart button. Try to click it fast 10 times for example. But in general, it works after commented.