Most of you probably heard already about “responsive website” but RESS is starting to become more and more popular and is especially used in large web applications.

Responsive website – The user interface is resizing or is showing/hiding different parts of the website depending on the screen size.  This means that the same content will be loaded for desktops and mobiles but just the UI is different.

RESS(Responsive Design + Server Side Components) – Rather than showing/hiding the content depending on the screen size, it will be generated depending on the device used to access the website. This means faster loading and less bandwidth used. For example if I would use RESS for this blog, I could use different image sizes for different devices or exclude the right sidebar for mobile devices so it will never load.

But RESS is not just that. You could even target content depending on the operating system or device brand. If a website is accessed from an Android phone you could show a URL to Google Play for the Android app or for iOS a URL to the App Store. If the website is accessed from a desktop, both URLs could show to advertise the apps.

The device detection will probably not be 100% accurate but it will be at least 90%. I used Safari on my Android phone to log in into a Gmail account and I received an email saying that someone logged in from an iOS device.

Another important thing is the way animations are used. If you’re using Javascript or CSS3 for animations and transitions you will probably see that they’re not as nice and smooth on mobile devices compared to desktops. That’s because these animations take a lot of memory and processor resources. These are also an enemy for batteries. A website with many animations uses more battery than a simple website. If you are using a CMS for your website such as WordPress it won’t be very easy to use RESS. It depends on how many plugins and what theme you’re using. You might have to modify each plugin manually. Even though you’re updating each plugin manually it will be hard to maintain them every time there is an update available.

I started using RESS about 2 years ago. I can’t say I’m an expert but I would say if a website is not using RESS then is not really responsive. Only the user interface might be responsive but the content is still loading slow on mobile devices even though probably only 50% of the content is visible. I find annoying when I visit a website which only has a few lines of text but takes 30 seconds to load. There are still people with limited mobile internet and I don’t think they would want to use 10mb just to load your fancy large images and hidden content.