Javascript check user agent

viewport.js

// VIEWPORT SETTINGS
/*
if (navigator.userAgent.indexOf('iPhone') != -1) {
	document.write('<meta name="viewport" content="width=480px, maximum-scale=1.0, user-scalable=0">');
}
if (navigator.userAgent.indexOf('iPad') != -1) {
	document.write('<meta name="viewport" content="width=1024px, maximum-scale=1.0, user-scalable=0">');
}
if (navigator.userAgent.indexOf('Android') != -1) {
}*/

var deviceSettings = {
    isAndroid: null,
    isEarlyIE: null,
    isIE: null,
    isiPod: null,
    isiPhone: null,
    isiPad: null,
    isiOS: null,
    isMobile: null,
    isTablet: null,
    isWinSafari: null,
    isMacSafari: null
	},
	startPos,
	endPos,
	inTransition = false;

function setupDeviceSettings() {
    var ua = navigator.userAgent.toLowerCase();
    deviceSettings.isAndroid = ua.indexOf("android") > -1;
    deviceSettings.isEarlyIE = (jQuery.browser.msie == true && Number(jQuery.browser.version) <= 8) ? true : false;
    deviceSettings.isIE = jQuery.browser.msie == true;
    deviceSettings.isiPod = navigator.userAgent.match(/iPod/i) != null;
    deviceSettings.isiPhone = navigator.userAgent.match(/iPhone/i) != null;
    deviceSettings.isiPad = navigator.userAgent.match(/iPad/i) != null;
    deviceSettings.isiOS = (navigator.userAgent.match(/(iPad|iPhone|iPod)/i) ? true : false);
    //determine if this is a mobile browser:
    var p = navigator.platform.toLowerCase();
    if (deviceSettings.isAndroid || deviceSettings.isiPad || p === 'ipad' || p === 'iphone' || p === 'ipod' || p === 'android' || p === 'palm' || p === 'windows phone' || p === 'blackberry' || p === 'linux armv7l') {
        deviceSettings.isMobile = true;
    }
	var safari = ($.browser.webkit && !(/chrome/.test(navigator.userAgent.toLowerCase())));
	var windows = (ua.indexOf("windows") !== -1);
	var mac = (ua.indexOf("mac") !== -1);
	if (safari && windows) {
		deviceSettings.isWinSafari = true;
	}
	if (safari && mac) {
		deviceSettings.isMacSafari = true;
	}
	
	
	 /*if (deviceSettings.isAndroid || p === 'iphone' || p === 'ipod' || p === 'android' || p === 'palm' || p === 'windows phone' || p === 'blackberry' || p === 'linux armv7l') {
		document.write('<meta name="viewport" content="width=480px, maximum-scale=1.0, user-scalable=0">');
	    }
	    if (deviceSettings.isiPad || p === 'ipad') {
			document.write('<meta name="viewport" content="width=1024px, maximum-scale=1.0, user-scalable=0">');
	    }*/
}