https://www.forestasia.com/tools/resolution.asp – A good resource for quickly seeing how a live site or page looks in a variety of screen resolutions, including smaller resolutions for Blackberries and mobile devices.
https://www.anybrowser.com/ScreenSizeTest.html – Another site for testing screen size (more limited options) – along with useful tables outlining actual "live areas" in pixels after the header bar and scrolling nav is accounted for.
https://www.htmlgoodies.com/beyond/javascript/article.php/3471261 – Simple bit of javascript code that will detect and display your users screen size in text on the page.
https://www.w3schools.com/browsers/browsers_stats.asp – Site offers a range of statistics on browser use, operating platforms, and screen resolution figures.
