browser_detect.js

var BrowserDetect = {
        init: function() {
		this.browser = this.searchString(this.dataBrowser) || "An unknown browser";
		this.version = this.searchVersion(navigator.userAgent) || this.searchVersion(navigator.appVersion) || "an unknown version";
		this.OS = this.searchString(this.dataOS) || "an unknown OS";
	},
	searchString: function(data) {
		for (var i = 0; i < data.length; i++) {
			var dataString = data[i].string;
			var dataProp = data[i].prop;
			this.versionSearchString = data[i].versionSearch || data[i].identity;
			if (dataString) {
				if (dataString.indexOf(data[i].subString) != -1) return data[i].identity;
			} else if (dataProp) return data[i].identity;
		}
	},
	searchVersion: function(dataString) {
		var index = dataString.indexOf(this.versionSearchString);
		if (index == -1) return;
		return parseFloat(dataString.substring(index + this.versionSearchString.length + 1));
	},
	dataBrowser: [{
		string: navigator.userAgent,
		subString: "Chrome",
		identity: "Chrome"
	}, {
		string: navigator.userAgent,
		subString: "OmniWeb",
		versionSearch: "OmniWeb/",
		identity: "OmniWeb"
	}, {
		string: navigator.vendor,
		subString: "Apple",
		identity: "Safari",
		versionSearch: "Version"
	}, {
		prop: window.opera,
		identity: "Opera",
		versionSearch: "Version"
	}, {
		string: navigator.vendor,
		subString: "iCab",
		identity: "iCab"
	}, {
		string: navigator.vendor,
		subString: "KDE",
		identity: "Konqueror"
	}, {
		string: navigator.userAgent,
		subString: "Firefox",
		identity: "Firefox"
	}, {
		string: navigator.vendor,
		subString: "Camino",
		identity: "Camino"
	}, { // for newer Netscapes (6+)
		string: navigator.userAgent,
		subString: "Netscape",
		identity: "Netscape"
	}, {
		string: navigator.userAgent,
		subString: "MSIE",
		identity: "Explorer",
		versionSearch: "MSIE"
	}, {
		string: navigator.userAgent,
		subString: "Gecko",
		identity: "Mozilla",
		versionSearch: "rv"
	}, { // for older Netscapes (4-)
		string: navigator.userAgent,
		subString: "Mozilla",
		identity: "Netscape",
		versionSearch: "Mozilla"
	}],
	dataOS: [{
		string: navigator.platform,
		subString: "Win",
		identity: "Windows"
	}, {
		string: navigator.platform,
		subString: "Mac",
		identity: "Mac"
	}, {
		string: navigator.userAgent,
		subString: "iPhone",
		identity: "iPhone/iPod"
	}, {
		string: navigator.platform,
		subString: "Linux",
		identity: "Linux"
	}]

};
BrowserDetect.init();

///// mobile
var isMobile = {
    Android: function() {
        return navigator.userAgent.match(/Android/i);
    },
    BlackBerry: function() {
        return navigator.userAgent.match(/BlackBerry/i);
    },
    iOS: function() {
        return navigator.userAgent.match(/iPhone|iPad|iPod/i);
    },
    Opera: function() {
        return navigator.userAgent.match(/Opera Mini/i);
    },
    Windows: function() {
        return navigator.userAgent.match(/IEMobile/i);
    },
    any: function() {
        return (isMobile.Android() || isMobile.BlackBerry() || isMobile.iOS() || isMobile.Opera() || isMobile.Windows());
    }
};

sample_detect.js

if (BrowserDetect.browser === 'Safari' && BrowserDetect.version < 6) {

	//Javascript goes here

}