The problem on your website will be this, that probably your theme uses Gantry 4, which is outdated. It uses MooTools, which has many known issues, including the one you are experiencing, that they are removing native js functions, like bind().
There are two things I can suggest:
- If your theme is still being kept updated by its developers, get in touch with them. Show them our documentation and ask them to modify the mootools.js file (they might use a different name) according to the documentation.
- If your theme is outdated, so it isn’t developed anymore and you can just modify its codes, follow our documentation. By checking the source code of your website (right click anywhere on the page -> View page source), you could try to search (Ctrl + F) for the word “mootools”, and try to find a .js file. Once you find the mootools js file, open it up on your FTP to edit it. Remove the code our documentation suggests too:
delete Function.prototype.bind,
After that if you hard refresh your page (Ctrl + SHIFT + F), to ensure browser cache won’t load the older file, then your problem should be resolved!