Animating Bootstrap progress bar width with jQuery

问题:

I want to animate a progress bar's width from 0% to 70% over 2.5 seconds. However, the code below immediately changes the width to 70% after a 2.5 second delay. What am I missing?

$(".progress-bar").animate({
    width: "70%"
}, 2500);

JSFiddle: http://jsfiddle.net/WEYKL/

回答1:

The problem is in default Bootstrap transition effect, which animates any update of the width property.

If you switch it off with supressing the corresponding style, it will work fine, e.g.:

.progress-bar {
    -webkit-transition: none !important;
    transition: none !important;
}

DEMO: http://jsfiddle.net/WEYKL/1/

回答2:

IT'S very EASY if uses bootstrap progress bar,

only add attrib aria-valuenow="percent_required%" to div with class "progress-bar" like this:

<div class="progress-bar progress-bar-success" role="progressbar" aria-valuenow="57%" aria-valuemin="0" aria-valuemax="57">

Next, on script:

<script>
  $(document).on('ready',function(){
    $('.progress .progress-bar').css("width",function() {
      return $(this).attr("aria-valuenow") + "%";
    })
  })
</script>

Reload, Go!

回答3:

So, it makes more sense to adjust the transition effect via CSS or jQuery.

.progress-bar {
    -webkit-transition: width 2.5s ease;
    transition: width 2.5s ease;
}

And just change the width value.

$(".progress-bar").css('width', '70%');

回答4:

You can fix it by adding:

.progress .progress-bar {
  transition: unset;
}

var delay = 500;
$(".progress-bar").each(function(i) {
  $(this).delay(delay * i).animate({
    width: $(this).attr('aria-valuenow') + '%'
  }, delay);

  $(this).prop('Counter', 0).animate({
    Counter: $(this).text()
  }, {
    duration: delay,
    // easing: 'swing',
    step: function(now) {
      $(this).text(Math.ceil(now) + '%');
    }
  });
});

.progress {
  margin-bottom: 20px;
}

.progress-bar {
  width: 0;
}

.bg-purple {
  background-color: #825CD6 !important;
}

.progress .progress-bar {
  transition: unset;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"></script>

<div class="container">
  <h2>Bootstrap 4 Progress Bars</h2>
  <div class="progress border">
    <div class="progress-bar progress-bar-striped progress-bar-animated bg-danger" role="progressbar" aria-valuenow="70" aria-valuemin="0" aria-valuemax="100">70</div>
  </div>
  <div class="progress border">
    <div class="progress-bar progress-bar-striped progress-bar-animated" role="progressbar" aria-valuenow="50" aria-valuemin="0" aria-valuemax="100">50</div>
  </div>
  <div class="progress border">
    <div class="progress-bar progress-bar-striped progress-bar-animated bg-purple" role="progressbar" aria-valuenow="90" aria-valuemin="0" aria-valuemax="100">90</div>
  </div>
</div>