Check browser's cache for a js file

Question

How can I check for a javascript file in user\'s cache. If he refreshed the page or visits the site after sometime. I need not download that js file again. Does the js file

Answer 1

The browser will take care of caching for you.

When the cache is emptied depends partly on the browser settings and partly on the headers you send. If you set an Expires header, then the browser shouldn't re-request the file until it has expired. Reading about HTTP Headers might help you.