具有渐变颜色的Bootstrap进度条,在活动宽度上按比例显示

Question

我需要创建一个由渐变颜色填充的Bootstrap进度条(让我们说红色到绿色).我的CSS目前看起来像这样:

.progress-lf {
    position: relative;
    height: 31px;
    background-color: rgba(51, 51, 51, 0.4)
}

.progress-lf span {
    position: absolute;
    display: block;
    font-weight: bold;
    color: #d2d2d2;
    width: 100%;
    top:6px;
}

.progress-lf .gradient {
    background-color: transparent;
    background-image: -ms-linear-gradient(left, #E34747 0%, #5FB365 100%);
    background-image: -moz-linear-gradient(left, #E34747 0%, #5FB365 100%);
    background-image: -o-linear-gradient(left, #E34747 0%, #5FB365 100%);
    background-image: -webkit-gradient(linear, left top, right top, color-stop(0, #E34747), color-stop(100, #5FB365));
    background-image: -webkit-linear-gradient(left, #E34747 0%, #5FB365 100%);
    background-image: linear-gradient(to right, #E34747 0%, #5FB365 100%);
}

和它一起使用的HTML是这样的:

    <div class="progress progress-lf">
            <div class="progress-bar gradient" role="progressbar" aria-valuenow="60" aria-valuemin="0" aria-valuemax="100" style="width: <?php echo mt_rand(0,100);?>%;">
                    <span>60% Complete</span>
            </div>
    </div>

这会显示渐变,但对于上面的示例(60%),它会在活动的60%区域中显示整个渐变色谱.我需要改变它,以便(例如)60%,只显示60%的渐变色谱.

有人对如何实现这个有任何想法吗？我更喜欢纯CSS解决方案,但如果需要jQuery来实现这一点,那也没问题.

Answer 1

为了让你动态改变'金额',我建议使用jquery(或vanilla js,无论哪个是首选)来调整进度条.

我已经使用了data-attribute来完成进度条的值以及文本(所以你只需要在一个地方更改它).

这意味着您所要做的就是改变

data-amount 

属性为0到100%之间的值.

演示

 $(document).ready(function () {
    var dataval = parseInt($('.progress').attr("data-amount"));
    if (dataval < 100) {
        $('.progress .amount').css("width", 100 - dataval + "%");
    }

  /*FOR DEMO ONLY*/
    $('#increase').click(function () {
        modifyProgressVal(1);
    });
    $('#decrease').click(function () {
        modifyProgressVal(-1);
    });
    function modifyProgressVal(type) {
        dataval = parseInt($('.progress').attr("data-amount"));
        if (type == 1) dataval = Math.min(100,dataval + 10)
        else if (type == -1) dataval = Math.max(0,dataval - 10);
        $('.progress .amount').css("width", 100 - dataval + "%");
        $('.progress').attr("data-amount", dataval);
    }
});

.progress {
  position: relative;
  height: 31px;
  background: rgb(255, 0, 0);
  background: -moz-linear-gradient(left, rgba(255, 0, 0, 1) 0%, rgba(0, 255, 0, 1) 100%);
  background: -webkit-gradient(linear, left top, right top, color-stop(0%, rgba(255, 0, 0, 1)), color-stop(100%, rgba(0, 255, 0, 1)));
  background: -webkit-linear-gradient(left, rgba(255, 0, 0, 1) 0%, rgba(0, 255, 0, 1) 100%);
  background: -o-linear-gradient(left, rgba(255, 0, 0, 1) 0%, rgba(0, 255, 0, 1) 100%);
  background: -ms-linear-gradient(left, rgba(255, 0, 0, 1) 0%, rgba(0, 255, 0, 1) 100%);
  background: linear-gradient(to right, rgba(255, 0, 0, 1) 0%, rgba(0, 255, 0, 1) 100%);
  filter: progid: DXImageTransform.Microsoft.gradient(startColorstr='#ff0000', endColorstr='#00ff00', GradientType=1);
}
.amount {
  position: absolute;
  top: 0;
  right: 0;
  height: 100%;
  transition: all 0.8s;
  background: gray;
  width: 0;
}
.progress:before {
  content: attr(data-amount)"% Complete";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 10;
  text-align: center;
  line-height: 31px;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<div class="progress" data-amount="80">
  <div class="amount"></div>
</div>


<!--FOR DEMO ONLY-->

<button id="increase">Increase by 10</button>
<button id="decrease">Decrease by 10</button>

这实际上只使用了两个元素,所以应该是非常好的性能.

注意

在这个答案中似乎有相当多的jQuery使用; 这是由于DEMO而非实际使用.