How to create a search results web page and store a large list of items without SQLDatabase

Question

I made a web page for selling items online. The website has a lot of products but will probably have multiple thousand products in the near future. The website contains a search bar and I want to create a search results page, but I am not sure what the best way of doing this is. I thought about using JavaScript to loop through the list of all the products until it finds a match. But this process is probably too slow. My question is: What is the best way to store a large list of items, and what is the best way to find matches from the list for the search query? I now that many people use SQL databases for storing lists but is that method any better than simply storing everything in a JavaScript list, and why? Also how do I find a match in the list? Can I use JavaScript or is it necessary or better to use a language like PHP?