supportspositionfixed.js

var supportsPositionFixed = (function() {
    var w   = window,
        ua  = navigator.userAgent,
        ret = true;
	
    // Black list the following User Agents
    if (
        // IE less than 7.0
        (/MSIE (\d+\.\d+);/i.test(ua) && RegExp.$1 < 7)          ||
        // iOS less than 5
        (/OS [2-4]_\d(_\d)? like Mac OS X/i.test(ua))            ||
        // Android less than 3
        (/Android ([0-9]+)/i.test(ua) && RegExp.$1 < 3)          ||
        // Windows Phone less than 8
        (/Windows Phone OS ([0-9])+/i.test(ua) && RegExp.$1 < 8) ||
        // Opera Mini
        (w.operamini && ({}).toString.call( w.operamini ) === "[object OperaMini]") ||
        // Kindle Fire
        (/Kindle Fire/i.test(ua) || /Silk\//i.test(ua)) ||
        // Nokia Symbian, Opera Mobile, wOS
        (/Symbian/i.test(ua)) || (/Opera Mobi/i.test(ua)) || (/wOSBrowser/i.test(ua)) ||
        // Firefox Mobile less than 6
        (/Fennec\/([0-9]+)/i.test(ua) && RegExp.$1 < 6)
        // Optionally add additional browsers/devices here . . .
        ){
        ret = false;
    }
    return ret;
})();