I analyzed my website on Gtmetrix.com for optimization and the result was this:
There are 4 static components without a far-future expiration date:
http://www.someextensionsite.com/widgets/v1.0/init.js http://static.someextensionsite.com/templates.0p4D3v0p5f.js http://static.someextensionsite.com/styles.0p4D3v0p5f.css http://static.someextentionsite.com/preload_data.0p4D3v0p5f.js
Expires headers let the browser know whether to server a cached version of the page.
and i should add this: someextentionsite is a search extentin.
how to solve this problem?