duplicate.js is a tiny, useful, jQuery based duplicate window checker that checks if a browser tab/window is already opened using pure JavaScript.
jQuery Plugin
Easy Browser/Device/Feature Detection Plugin For jQuery - checkit.js
qTip2 - Advanced Tooltip Plugin For jQuery
jQuery Plugin To Detect If The Browser Gets Or Losts Focus
jQuery Based Viewport Size And isTouch Checker - viewportInfo
jQuery Plugin To Detect The Version Of Web Browsers - getBrowser
Prevent Webpage From Being Opened In Multiple Tabs - duplicateWindow
jQuery Lightweight Accordion Plugin - Zebra_Accordion
Detect Browser, Device and OS With jQuery - js.device.detector
Check Duplicate Browser Tabs/Windows With jQuery - duplicate.js
Auto Pass CSS Breakpoints To JavaScript - js.device.selector