I am new to function and I am looking for some help understand how to make a function that will work under the Zoho sites.

I can add a function in the Header/footer where this fucntion can be writen.
Then in the page it self i can add some HTML code to call this function but i an not sure how to make it work.

The only thread in Zoho Sites Community i found is this: https://help.zoho.com/portal/en/community/topic/show-more-and-show-less-text

Can someone help me the basics?
Kind Regards

Having a compatible code that could work under the Zoho sites.