jquery - 在div View 上执行JQuery函数

Question

我想知道当“about”div 处于 View 中时如何激活此 jQuery。 或者当我们滚动 div 时。

(function($) {
  $.fn.countTo = function(options) {
    options = options || {};

    return $(this).each(function() {

      var settings = $.extend({}, $.fn.countTo.defaults, {
        from: $(this).data('from'),
        to: $(this).data('to'),
        speed: $(this).data('speed'),
        refreshInterval: $(this).data('refresh-interval'),
        decimals: $(this).data('decimals')
      }, options);


      var loops = Math.ceil(settings.speed / settings.refreshInterval),
        increment = (settings.to - settings.from) / loops;


      var self = this,
        $self = $(this),
        loopCount = 0,
        value = settings.from,
        data = $self.data('countTo') || {};

      $self.data('countTo', data);


      if (data.interval) {
        clearInterval(data.interval);
      }
      data.interval = setInterval(updateTimer, settings.refreshInterval);


      render(value);

      function updateTimer() {
        value += increment;
        loopCount++;

        render(value);

        if (typeof(settings.onUpdate) == 'function') {
          settings.onUpdate.call(self, value);
        }

        if (loopCount >= loops) {
          // remove the interval
          $self.removeData('countTo');
          clearInterval(data.interval);
          value = settings.to;

          if (typeof(settings.onComplete) == 'function') {
            settings.onComplete.call(self, value);
          }
        }
      }

      function render(value) {
        var formattedValue = settings.formatter.call(self, value, settings);
        $self.html(formattedValue);
      }
    });
  };

  $.fn.countTo.defaults = {
    from: 0,
    to: 0,
    speed: 1000,
    refreshInterval: 100,
    decimals: 0,
    formatter: formatter,
    onUpdate: null,
    onComplete: null
  };

  function formatter(value, settings) {
    return value.toFixed(settings.decimals);
  }
}(jQuery));

jQuery(function($) {
  // custom formatting example
  $('.count-number').data('countToOptions', {
    formatter: function(value, options) {
      return value.toFixed(options.decimals).replace(/\B(?=(?:\d{3})+(?!\d))/g, ',');
    }
  });


  $('.timer').each(count);

  function count(options) {
    var $this = $(this);
    options = $.extend({}, options || {}, $this.data('countToOptions') || {});
    $this.countTo(options);
  }
  $(function() {
    $('div[onload]').trigger('onload');
  });
});

Answer 1

您可以将代码设置为非匿名函数，并使用 jQuery 的 Waypoints 插件来触发该函数。

如果您不想使用插件，则可以触发 $(window).scroll() 内的函数并进行一些计算。首先注释掉这一行:$('.timer').each(count);。您可以将该行包裹在滚动检查器内，如下所示:

//listening scrolling action

$(window).scroll(function() {
    var div_start = $("#about-row-b").offset().top;
    var div_final = $("#about-row-b").offset().top + $("#about-row-b").outerHeight();
    var viewport_end = $(window).scrollTop() + $(window).height();

    if((viewport_end > div_start) && (viewport_end < div_final)){
        // v v v call your function here!!!
        $('.timer').each(count);
    }
});

如果您只对上升的数字感兴趣，您可能需要检查 Benjamin Intal's Counter Up jQuery plugin .