I am trying to set expiration time of contents of my website so to increase website performance and have a good page speed insight. I am able to set expiration time for elements that resides on my server but some of the elements which are loaded from other servers (CDN, social networking sites etc.) have "expiration not specified". Following is an example:
http://platform.twitter.com/…c4c981cd3f8f8dfb6b0ab93d6a9e.default.css (expiration not specified)
due to these elements, PageSpeed insight of google developer shows an error to fix "Leverage browser caching" Below is the path for PageSpeed insight for reference:
https://developers.google.com/speed/pagespeed/insights/?url=http%3A%2F%2Fwww.wiwigo.com%2Fblog
how can I set the expiration for such elements?