Not sure how to make use of cache?

Not sure how to make use of cache?

  2. if (!sessionStorage.getItem('GotTags')) {
  3.         $.ajax({
  4.             url: "Search/GetTags",
  5.             method: "GET",
  6.             datatype: "json",
  7.             success: function (data) {
  8.                 sessionStorage.setItem("tags", JSON.stringify(data.songTags.concat(data.albumTags, data.artistTags)));
  9.                 sessionStorage.setItem('GotTags', 'true');
  10.             }
  11.         });
  12.     }

  14.     $("#searchString").autocomplete({
  15.         source: function (request, response) {
  16.             var tags = JSON.parse(sessionStorage.getItem("tags"));
  17.             var results = $.ui.autocomplete.filter(tags, request.term);

  19.             response(results.slice(0, 10));
  20.         },
  21.         minLength: 3
  22.     });

Okay so the code above gets the tags and stores them in session variable, I only do this once so that it doesn't go through each time the page is refreshed.

My question is can I make use of the Ajax cache to store this information and only go through the function if it isn't cached or is my way fine?

I am not sure how cache works properly yet, how can I access cached variables?