跟踪在页面上显示某些元素所花费的时间

Question

所以假设我们有4个Div(3个隐藏,1个可见),用户可以通过javascript/jQuery在它们之间切换.

我想计算在每个Div上花费的时间,并将包含该时间的xhr发送到服务器以将其存储在数据库中.当用户切换div视图时,将发送此xhr.

我怎样才能做到这一点？任何提示将不胜感激.

谢谢,

Answer 1

在任何时候,您都可以在变量中记录开始/单圈时间:

var start = new Date();

如果要计算经过的时间,只需从新的Date实例中减去存储的日期:

var elapsed = new Date() - start;

这将为您提供经过的时间(以毫秒为单位).做额外的数学(除法)来计算秒,分钟等.

Answer 2

干得好:

HTML:

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

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

JavaScript的:

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);

现场演示: http ://jsfiddle.net/7svZr/2/

我保持时间以毫秒为单位,因为整数更清晰,更安全(0.1 + 0.2 != 0.3).请注意,您可以通过设置delay变量来调整"精度"(间隔函数的延迟).

Answer 3

这是一个可重用的类，示例包含在代码中：

/*
     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