Check if user is using IE

Question

I am calling a function like the one below by click on divs with a certain class.

Is there a way I can check when starting the function if a user is using Internet

Answer 1

Many answers here, and I'd like to add my input. IE 11 was being such an ass concerning flexbox (see all its issues and inconsistencies here) that I really needed an easy way to check if a user is using any IE browser (up to and including 11) but excluding Edge, because Edge is actually pretty nice.

Based on the answers given here, I wrote a simple function returning a global boolean variable which you can then use down the line. It's very easy to check for IE.

var isIE;
(function() {
    var ua = window.navigator.userAgent,
        msie = ua.indexOf('MSIE '),
        trident = ua.indexOf('Trident/');

    isIE = (msie > -1 || trident > -1) ? true : false;
})();

if (isIE) {
    alert("I am an Internet Explorer!");
}

This way you only have to do the look up once, and you store the result in a variable, rather than having to fetch the result on each function call. (As far as I know you don't even have to wait for document ready to execute this code as the user-agent is not related to the DOM.)