How to change/update image dynamically using amp-bind in Google AMP ?️‍🔥

Sometimes you want to add custom interactivity to your AMP pages to make your pages look more user-friendly and user calling. Although AMP’s pre-built components are limited, so amp-bind is made to overcome this problem. It helps the developer to add custom interactivity to the pages without using AMP’s pre-built components. You can use amp-bind to change the text dynamically on user interaction with the page.

Setup: To use amp-bind in your page you have to import its script in the header of the document.

HTML

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

The amp-bind of Google AMP comprises three main concepts:

State: State variables are responsible for the update on the page on the basis of user actions. It is very important to define a state variable.
Expression: They are like JavaScript expressions used to refer to the state.
Binding: They are a special attribute that is used to link an element’s property to a state via an expression.

Example:

HTML

<!doctype html>
<html amp>
 
<head>
    <meta charset="utf-8">
    <title>Google 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>
 
    <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;
        }
 
        .gfgNew {
            border: 5px solid crimson;
        }
 
        .gfgOld {
            border: 5px solid orange;
        }
    </style>
</head>
 
<body>
    <h1>
        Beginner For Beginner
    </h1>
 
    <amp-state id="gfg">
        <script type="application/json">
          {
            "new": {
              "imageUrl": 
"https://media.w3wiki.net/wp-content/cdn-uploads/gfg_200x200-min.png",
              "style": "gfgNew"
            },
            "old": {
              "imageUrl": 
"https://media.w3wiki.net/wp-content/uploads/20201026154131/logogfg.png",
              "style": "gfgOld"
            }
        }
      </script>
    </amp-state>
 
    <div style="padding: 1em;">
         
<p>
            Each logo has different border color...
        </p>
 
        <h4 ="'This is ' + logo + ' logo...'">
            This is old logo...
        </h4>
        <center>
            <amp-img width="200" height="200" src=
"https://media.w3wiki.net/wp-content/uploads/20201026154131/logogfg.png"
                [src]="gfg[logo].imageUrl" 
                class="gfgOld"
                [class]="gfg[logo].style">
            </amp-img>
            <br>
            <button on="tap:AMP.setState({logo: 'new'})">
                New Logo
            </button>
            <button on="tap:AMP.setState({logo: 'old'})">
                Old Logo
            </button>
        </center>
    </div>
</body>
 
</html>

Output:

When New Logo button was hit, image and border color both got dynamically changed. When we hit Old Logo button image and border color changed to the previous combination.