Redo the javascript implementation on the website

A previous designer has delivered a working design based on Jquery and Bootstrap. Some of the javascript files have been taken from another site and appear to contain code that I do not recognize. I want help to go through all the javascript that is on the page, come up with suggestions for change and then help with the implementation and be support for further questions. The basis of the page is that menus should appear during onmouseover and clicks should close menus and open the search function. Some javascript is embedded on the page and some code is central, here it needs a structuring job. There is a calendar function on the booking page ([login to view URL]) that I want to redo, the design should be 100% of the width, week number must be in a column on the left. The code need to get validated and optimied. Homepage: [login to view URL] Product page: [login to view URL] All files are located at the website: <script src="[login to view URL]"></script> <script src="[login to view URL]"></script> <script src="[login to view URL]"></script> <script src="[login to view URL]"></script> <script src="[login to view URL]"></script> <script src="[login to view URL]"></script> <script src="[login to view URL]"></script> <script src="[login to view URL]"></script> <script src="[login to view URL]"></script> <script src="[login to view URL]"></script> <script src="[login to view URL]"></script> <script src="[login to view URL]"></script>