Vanilla JavaScript Check for Class on Element

Sometimes, devs can rely on jQuery a little too much, and forget how to check for a className without a framework to help. Granted

$(elem).hasClass("className");

is easy. But sometimes, one must go jquery free!

el.classList.contains(className);

However, the .contains is not supported by all browsers

So, you can always fallback to good oleindexOf

function hasClass(el, className) {
    return (' ' + el.className + ' ').indexOf(' ' + className+ ' ') > -1;
}