How to toggle the visibility of division using amp-bind in Google AMP?

Last Updated : 21 Dec, 2020

Introduction: 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.

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

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

amp-bind of Google AMP is comprised of 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: Dynamically hiding and showing divisions on the basis of the option selected.

<!DOCTYPE html> 
<html amp> 
  
<head> 
    <meta charset="utf-8" /> 
    <title>GeeksForGeeks | 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 the 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; 
        } 
    </style> 
</head> 
  
<body> 
    <center> 
        <h1>Geeks For Geeks</h1> 
    </center> 
  
    <!-- This sample toggles the visibility of  
        two divs based on a input selection.  
        AMP provides the [`hidden` attribute],  
        which we use to hide and show the two  
        divs. Some elements, such as the `select`  
        element, fire [events] we can use to  
        update state -->
    <div style="padding: 1em; color: crimson;"> 
        <label><u>Select the option</u>: </label> 
        <select on="change:AMP.setState 
                    ({option: event.value})"> 
            <option value="0">No selection</option> 
            <option value="1">Option 1</option> 
            <option value="2">Option 2</option> 
        </select> 
        <br /> 
  
        <div hidden [hidden]="option != 1"> 
            <h3>You have selected Option 1</h3> 
        </div> 
          
        <div hidden [hidden]="option != 2"> 
            <h3>You have selected Option 2</h3> 
        </div> 
    </div> 
</body> 
  
</html> 