jQuery addClass example

Change class name on click in jQuery

HTML

<p>zoom levels (open console)</p>

JavaScript

function browserCheck()
{	
	//console.log(navigator.userAgent)
    //Check if browser is Edge
    if (navigator.userAgent.search("Edge") >= 0) { return 'edge'; }
    //Check if browser is IE
    else if (navigator.userAgent.search("Trident") >= 0) { return 'msie'; }
    //Check if browser is Chrome
    else if (navigator.userAgent.search("Chrome") >= 0) { return 'chrome'; }
    //Check if browser is Firefox 
    else if (navigator.userAgent.search("Firefox") >= 0) { return 'firefox'; }
    //Check if browser is Safari
    else if (navigator.userAgent.search("Safari") >= 0 && navigator.userAgent.search("Chrome") < 0) { return 'safari'; }
    //Check if browser is Opera
    else if (navigator.userAgent.search("Opera") >= 0) { return 'opera'; } 
    //Check if browser is other
    else { return 'other'; } 
}

function getZoom_IE() {
	return ((document.frames.screen.deviceXDPI / document.frames.screen.systemXDPI) * 100 + 0.1).toFixed();
}	

function getZoom_Chrome() {
	return (window.devicePixelRatio*100).toFixed(0) || 1;
}		

function getZoom_Firefox() {
	var searchDPPX = function(level, min, divisor) {
	var wmq = window.matchMedia;
	while (level >= min && !wmq("(min-resolution: " + (level / divisor) + "dppx)").matches) {level--;}
	return level;
	};
	var maxDPPX = 5.0, minDPPX = 0.1, divisor = 1, result;
	for (var i = 0; i < 2; i++) {
	result = 10 * searchDPPX(maxDPPX, minDPPX, divisor);
	maxDPPX = result + 9;
	minDPPX = result;
	divisor *= 10;
	}
	return (result / divisor)*100;
}	

function getZoomLevels()
{
	//tailor the calcs to the browser
	if(browserCheck() == 'chrome')
		{final = getZoom_Chrome();}//nothing to do, Chrome is awesome	
	else if(browserCheck() == 'msie')
		{final = getZoom_IE();}
	else if(browserCheck() == 'firefox')
		{final = getZoom_Firefox();}
	else
		{final = 0;}
	 return final;	
}


$( window ).resize(function()  {console.log('Zoom: ' + getZoomLevels());});	
$( document ).ready(function() {console.log('Zoom: ' + getZoomLevels());});