You might use a local web server for testing your websites and scripts. Usually, there is no need to use SSL.
After deploying to your HTTPS production environment, some features like JQuery AutoComplete etc. might not work any more, but they do work if you call them via common HTTP.
Have a look at the Firefox F12 Debug Console, there could be also messages that some content was blocked on page load.
You replace the http:// string with https:// in your code.
Better method, which I recommend: Delete the string „http:“. Example:
Of course, the site provided has to be accessible via HTTP and HTTPS.