Twitter Bootstrap - how to detect when media queries starts

Question

which is the fastest and easy way to fire when bootstrap-responsive.css media queries go in action?

go in action = when you resize window to mobile width and site is

Answer 1

I came up with an approach that uses window resize event, but relying on Twitter Bootstrap's media queries without hard coding their breakpoints:

---

#mq-detector {
    visibility: hidden;
}

---

var currMqIdx = undefined;
var mqDetector = $("#mq-detector");
var mqSelectors = [
    mqDetector.find(".visible-xs"),
    mqDetector.find(".visible-sm"),
    mqDetector.find(".visible-md"),
    mqDetector.find(".visible-lg")
];

var checkForResize = function() {
    for (var i = 0; i <= mqSelectors.length; i++) {
        if (mqSelectors[i].is(":visible")) {
            if (currMqIdx != i) {
                currMqIdx = i;
                console.log(mqSelectors[i].attr("class"));
            }
            break;
        }
    }
};

$(window).on('resize', checkForResize);

checkForResize();