title: load div only for mobile devices with javascript
body: <p>Is it possible to load a div if a mobile is detected or if a resolution is lower than 641px?
  I have different menus for desktop and for mobile. Mobile menu uses image svg sprite, but for desktop i don't want that svg image to load to save HTTP request.
  I can hide the div based on media queries, but how can i at least prevent the image from being loaded, or load the intire menu div only for mobile?
  What is the best approach to this?</p>