Как динамически рассчитать площадь круга с помощью amp-bind-macro в Google AMP?

Опубликовано: 12 Апреля, 2022

С помощью amp-bind-macro можно создать программу HTML для динамического вычисления площади круга. Когда ввод задан, страница будет реагировать на ввод пользователя, найти область круга с заданным радиусом и распечатать его, не обновляя страницу.

Setup: To use amp-bind-macro in our AMP page, we have to import amp-bind script in the head of the document.

HTML

<script async custom-element="amp-bind" src=
"https://cdn.ampproject.org/v0/amp-bind-0.1.js">
</script>

Example:

HTML

<!doctype html>
<html amp>
  
<head>
    <meta charset="utf-8">
    <title>Foofle AMP amp-bind</title>
  
    <link rel="canonical" href=
"https://amp.dev/documentation/examples/components/amp-bind/index.html">
  
    <meta name="viewport" content=
"width=device-width,minimum-scale=1,initial-scale=1">
  
    <script async src=
        "https://cdn.ampproject.org/v0.js">
    </script>
  
    <!-- Import amp-bind component in header -->
    <script async custom-element="amp-bind" 
src="https://cdn.ampproject.org/v0/amp-bind-0.1.js">
    </script>
  
    <style amp-boilerplate>
        body {
            -webkit-animation: -amp-start 8s 
                steps(1, end) 0s 1 normal both;
              
            -moz-animation: -amp-start 8s 
                steps(1, end) 0s 1 normal both;
              
            -ms-animation: -amp-start 8s 
                steps(1, end) 0s 1 normal both;
              
            animation: -amp-start 8s 
                steps(1, end) 0s 1 normal both
        }
  
        @-webkit-keyframes -amp-start {
            from {
                visibility: hidden
            }
  
            to {
                visibility: visible
            }
        }
  
        @-moz-keyframes -amp-start {
            from {
                visibility: hidden
            }
  
            to {
                visibility: visible
            }
        }
  
        @-ms-keyframes -amp-start {
            from {
                visibility: hidden
            }
  
            to {
                visibility: visible
            }
        }
  
        @-o-keyframes -amp-start {
            from {
                visibility: hidden
            }
  
            to {
                visibility: visible
            }
        }
  
        @keyframes -amp-start {
            from {
                visibility: hidden
            }
  
            to {
                visibility: visible
            }
        }
    </style>
  
    <noscript>
        <style amp-boilerplate>
            body {
                -webkit-animation: none;
                -moz-animation: none;
                -ms-animation: none;
                animation: none
            }
        </style>
    </noscript>
  
    <style amp-custom>
        h1 {
            color: forestgreen;
            text-align: center;
        }
    </style>
</head>
  
<body>
    <h1>
        Geeks For Geeks
    </h1>
      
    <!-- [`amp-bind-macro`] makes it possible 
        to reuse expressions across different 
        actions -->
    <div style="padding: 1em;
                  color: crimson;">
        <amp-bind-macro id="circleArea" 
            arguments="radius" 
            expression="3.14 * radius * radius">
  
            <label>
                <u>Enter the radius of the circle</u>: 
            </label>
            <input type="number" min="0" max="100" 
                value="0" on="input-throttled:AMP.setState({
                      radius: event.value })">
            <br>
              
            <div>
                <h4>
                    The circle has an area of
                    <span ="circleArea(radius)">0</span>.
                </h4>
            </div>
        </amp-bind-macro>
    </div>
</body>
  
</html>

Выход:

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