Add Internet Explorer class to body to detect old browser

When you have clients that still uses an old browser, you need to handle it.
This javascript function detects the Microsoft browsers and add specific version for each one, so you can determine which browser is with CSS or with jQuery by controlling the class.
It adds a class msie | trident | edge to the body, together with a class ieXX, where XX is the browser version.

/**
* detect IE
* and add a specific class to the body
* function modified from this: http://stackoverflow.com/questions/19999388/check-if-user-is-using-ie-with-jquery
*/
function addIEclasses() {
	var ua = window.navigator.userAgent;
	var b = "";
	var msie = ua.indexOf('MSIE ');
	if (msie > 0) {
		// IE 10 or older => return version number
		b = "msie ie" + parseInt(ua.substring(msie + 5, ua.indexOf('.', msie)), 10);
	}

	var trident = ua.indexOf('Trident/');
	if (trident > 0) {
		// IE 11 => return version number
		var rv = ua.indexOf('rv:');
		b = "trident ie"+parseInt(ua.substring(rv + 3, ua.indexOf('.', rv)), 10);
	}

	var edge = ua.indexOf('Edge/');
	if (edge > 0) {
		// Edge (IE 12+) => return version number
		b = "edge ie"+parseInt(ua.substring(edge + 5, ua.indexOf('.', edge)), 10);

	}

	// other browser
	if(b!="") {
		$('body').addClass(b);
	}
}