recognizing client device size
I am building a singular jquery- mobile application that is accessed by Desktop-browsers, Tablets/iPad, Mobile-browsers (big screens) and mobile devices (smaller screens). I want to discard any mobiles that are too small (say smaller than a defined width and height, were I will show a not compatible message).
So this takes me to 4 categories:
1. Desktop
2. Tablet.
3. Smartphones with big screens.
4. Smartphones with smaller screens.
5. Smaller than 4th category which I will discard with an error message.
Is there any example code that I can write in PHP to know where the request is coming from?
I want to build 4 sets of images and based on the category, send the appropriate images and font sizes while responding with the content.
I am a beginner and am very sure that this is a common problem with solution crafted in a design pattern that you all follow. Where can I find it?