Posted: Sat Feb 24, 2007 5:56 am
Ah. Clever.
What they're doing is just displaying an image from their server. For example, imagine you have an HTML page with an image in it called "http://www.domain.com/upgrade.jpg" ... that just displays the image from domain.com. Using PHP you can dynamically generate an image (with GD). So if you set php properly you can call something like upgrade.jpg?version=123, and build an image based on that. Obviously you'd make a "you need to upgrade" image if the latest version was lower than the version passed in the GET request.
Essentially it completely bypasses PHP. It's just done in the browser. That's a very sensible approach really because it doesn't rely on URL wrappers or external calls of any sort being available on the server.
What they're doing is just displaying an image from their server. For example, imagine you have an HTML page with an image in it called "http://www.domain.com/upgrade.jpg" ... that just displays the image from domain.com. Using PHP you can dynamically generate an image (with GD). So if you set php properly you can call something like upgrade.jpg?version=123, and build an image based on that. Obviously you'd make a "you need to upgrade" image if the latest version was lower than the version passed in the GET request.
Essentially it completely bypasses PHP. It's just done in the browser. That's a very sensible approach really because it doesn't rely on URL wrappers or external calls of any sort being available on the server.