问记录在页面上显示某些元素所花费的时间

EN

var start = new Date();

var elapsed = new Date() - start;

<div id="divs">
    <div>First</div>
    <div class="selected">Second</div>
    <div>Third</div>
    <div>Fourth</div>
</div>

<p id="output"></p>

var divs = $('#divs > div'),
    output = $('#output'),
    tarr = [0, 0, 0, 0],
    delay = 100;

divs.click(function() {
    $(this).addClass('selected').siblings().removeClass('selected');
});

setInterval(function() {
    var idx = divs.filter('.selected').index();
    tarr[idx] = tarr[idx] + delay;
    output.text('Times (in ms): ' + tarr);
}, delay);

/*
     Help track time lapse - tells you the time difference between each "check()" and since the "start()"

 */
var TimeCapture = function () {
    var start = new Date().getTime();
    var last = start;
    var now = start;
    this.start = function () {
        start = new Date().getTime();
    };
    this.check = function (message) {
        now = (new Date().getTime());
        console.log(message, 'START:', now - start, 'LAST:', now - last);
        last = now;
    };
};

//Example:
var time = new TimeCapture();
//begin tracking time
time.start();
//...do stuff
time.check('say something here')//look at your console for output
//..do more stuff
time.check('say something else')//look at your console for output
//..do more stuff
time.check('say something else one more time')//look at your console for output