ajax-cache-parser

A small function to get when an ajax request expires

Given an XMLHttpRequest object that has received response headers back from a server, getCacheExpiry will return a javascript Date object that represents when the response will expire based on the Expires and Cache-Control response headers. If caching headers are not present or are unparseable, undefined will be returned. If caching headers indicate that the resource should not be cached, null will be returned.

Example

function callback(){
  var expiration = parser.getCacheExpiry(this);
  // do something with expiration
}
var oReq = new XMLHttpRequest();
oReq.onload = callback;
oReq.open("get", yourUrl, true);
oReq.send();

Information about caching headers comes from: https://www.mnot.net/cache_docs/