How to Check the If-Modified-Since Header
- 1). Open a Web browser on your computer. Navigate to http://www.feedthebot.com/tools/if-modified/.
- 2). Type your website into the "Enter URL" text box. Type your main URL or a Web page for your domain.
- 3). Click "Go" to check for the header. The tool returns the status of your server. If the website returns a green check mark, then your site uses the If-Modified-Since header.