No, you can't run elasticsearch offline on a web client.

Look, we can keep going back and forth and maybe you'll dig up some javascript library that implements a search. And that's fine, I believe there are "maker" roles that largely are about gluing things together and translating requirements into code and shouldn't require screening for CS fundamentals. But at some point it gets a little hacky and suboptimal if you lack a good practical grasp of computer science.