This simple web tool will allow you to view the HTTP header (or HTTPS header) that your web server is sending along with your files. You can use this web tool to verify that the correct MIME type (Content-type) is being sent for each file type. HTTP Header Viewer can be also useful if you need to know what cookies are being set or where any re-directs are going to.

HTTP headers are used to define a variety of qualities about a web object. For instance, if a webmaster is setting the cachability of a web site, HTTP headers such as Cache-Control, Expires, and Last-Modified would be used. New applications, such as P3P, often require information about the object to be sent via headers. It is important to note that an HTTP header is not the same as the META tag. META tags send information within the HTML page, while HTTP headers send information about the HTML page.


Source: http://www.headerviewer.com