Header

If the LastModified header is not returned when getting a file off a server, is it possible to manually request it?

I don't think so, it's just a server setting.

I gather that there is a If-Modified-Since request header. If I wanted a page that has been created after 1 Jan 2010, how can i create a header that does this, using the If-Modified-Since request header?

you could probably make a request using PHP and cURL, but this isn't something you can do with HTML or JavaScript.

what exactly are you trying to do?

I am a visual basic programmer wanting to make an application that detects when a web page has been updated.

This is how i want to do it...

1. The user specifies a page to be monitored
2. The date of the page is recorded
3. every 5 mins the date is checked and if it has changed, the user is notified by a messagebox.

The problem is that not all pages return the modified date in the response header... thats why i am thinking of using the If-Modified-Since request header.

Does that make sense?

I guess it makes sense, but I don't know how to help you do it; you're better off looking in the VB section of the forum.