如何使用 HTML 5 创建发光效果

Question

寻求帮助来实现 Stacks 新文档网站上看到的那个小蓝点，它非常适合为我正在构建的显示服务运行状况/指标的仪表板制作动画。我使用 Chrome 的检查器抓取了 html/css，但我对这些东西很糟糕，我什至无法得到一个点，更不用说一个发光的蓝色了；-D

https://jsfiddle.net/raffinyc/3trup2c1/

.help-bubble:after {
  content: "";
  background-color: #3af;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  position: absolute;
  display: block;
  top: 1px;
  left: 1px;
}
<span class="help-bubble-outer-dot">
        <span class="help-bubble-inner-dot"></span>
</span>

Answer 1

Here's the full reproduction。动画大量使用了伪元素。 CSS：

.help-bubble .help-bubble-outer-dot {
    margin: 1px;
    display: block;
    text-align: center;
    opacity: 1;
    background-color: rgba(0,149,255,0.4);
    width: 12px;
    height: 12px;
    border-radius: 50%;
    animation: help-bubble-pulse 1.5s linear infinite;
}

.help-bubble {
  display: block;
  position: absolute;
  z-index: 2;
  cursor: pointer;
  left: 40px;
  top: 40px;
}

.help-bubble::after {
    content: "";
    background-color: #3af;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    position: absolute;
    display: block;
    top: 1px;
    left: 1px;
}

.help-bubble .help-bubble-inner-dot {
    background-position: absolute;
    display: block;
    text-align: center;
    opacity: 1;
    background-color: rgba(0,149,255,0.4);
    width: 12px;
    height: 12px;
    border-radius: 50%;
    -webkit-animation: help-bubble-pulse 1.5s linear infinite;
    -moz-animation: help-bubble-pulse 1.5s linear infinite;
    -o-animation: help-bubble-pulse 1.5s linear infinite;
    animation: help-bubble-pulse 1.5s linear infinite;
}

.help-bubble .help-bubble-inner-dot:after {
    content: "";
    background-position: absolute;
    display: block;
    text-align: center;
    opacity: 1;
    background-color: rgba(0,149,255,0.4);
    width: 12px;
    height: 12px;
    border-radius: 50%;
    -webkit-animation: help-bubble-pulse 1.5s linear infinite;
    -moz-animation: help-bubble-pulse 1.5s linear infinite;
    -o-animation: help-bubble-pulse 1.5s linear infinite;
    animation: help-bubble-pulse 1.5s linear infinite;
}

@keyframes help-bubble-pulse{
  0% {
    transform: scale(1);
    opacity: .75;
  }
  25% {
    transform:scale(1);
    opacity:.75;
  }
  100% {
    transform:scale(2.5);
    opacity:0
  }
}

郑重声明，我对代码知识产权不是很精通，但如果不以某种方式将其变为自己的，您不太可能有权完全使用它。

Answer 2

试试box-shadow：

-webkit-box-shadow: 0px 0px 20px 0px rgba(0,225,255,1);
-moz-box-shadow: 0px 0px 20px 0px rgba(0,225,255,1);
box-shadow: 0px 0px 20px 0px rgba(0,225,255,1);

语法是：

0px (horizontal offset) 0px (vertical offset) 20px (bur value) 0px (spread value) rgba (color value)

查看这里了解更多信息：

https://css-tricks.com/snippets/css/css-box-shadow/