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Getting started with JavaScript CheckBox control

13 May 2021 / 3 minutes to read

This section explains how to create a simple CheckBox, and configure its available functionalities in TypeScript, using Essential JS 2 quickstart seed repository.

Dependencies

The following list of dependencies are required to use the CheckBox component in your application the.

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|-- @syncfusion/ej2-buttons
    |-- @syncfusion/ej2-base

Setup your development environment

To get started with the CheckBox component, you can clone the Essential JS 2 quickstart project and install the npm packages by using the following commands.

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git clone https://github.com/syncfusion/ej2-quickstart.git quickstart
cd quickstart
npm install

The project is preconfigured with common settings (src/styles/styles.css, system.config.js) to start all the Essential JS 2 components.

[src/system.config.js]

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System.config({
paths: {
    'npm:': './node_modules/',
    'syncfusion:': 'npm:@syncfusion/'
},
map: {
    app: 'app',

    //Syncfusion packages mapping
    "@syncfusion/ej2-base": "syncfusion:ej2-base/dist/ej2-base.umd.min.js",
    "@syncfusion/ej2-data": "syncfusion:ej2-data/dist/ej2-data.umd.min.js",
    "@syncfusion/ej2-inputs": "syncfusion:ej2-inputs/dist/ej2-inputs.umd.min.js",
    "@syncfusion/ej2-buttons": "syncfusion:ej2-buttons/dist/ej2-buttons.umd.min.js",
    "@syncfusion/ej2-splitbuttons": "syncfusion:ej2-splitbuttons/dist/ej2-splitbuttons.umd.min.js",
    "@syncfusion/ej2-lists": "syncfusion:ej2-lists/dist/ej2-lists.umd.min.js",
    "@syncfusion/ej2-popups": "syncfusion:ej2-popups/dist/ej2-popups.umd.min.js",
    "@syncfusion/ej2-dropdowns": "syncfusion:ej2-dropdowns/dist/ej2-dropdowns.umd.min.js",
},
packages: {
    'app': { main: 'app', defaultExtension: 'js' }
}
});

System.import('app.ts').catch(console.error.bind(console)).then(function () {
document.getElementById('loader').style.display = "none";
document.getElementById('container').style.visibility = "visible";
});

Add CheckBox to the project

Add the HTML input tag with id attribute as the element to your index.html file.

[src/index.html]

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<!DOCTYPE html>
<html lang="en">

<head>
<title>Essential JS 2</title>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no" />
<meta name="description" content="Essential JS 2" />
<meta name="author" content="Syncfusion" />
<link rel="shortcut icon" href="resources/favicon.ico" />
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" />

<!--style reference from app-->
<link href="/styles/styles.css" rel="stylesheet" />

<!--system js reference and configuration-->
<script src="node_modules/systemjs/dist/system.src.js" type="text/javascript"></script>
<script src="system.config.js" type="text/javascript"></script>
</head>

<body>
<div>
    <!--element which is going to render-->
    <input id="element" type="checkbox"/>
</div>

</body>

</html>

Import the CheckBox component in your app.ts file and initialize it to #element as shown in the following.

[src/app/app.ts]

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import { CheckBox } from '@syncfusion/ej2-buttons';

// Initialize CheckBox component.
let checkbox: CheckBox = new CheckBox({ label: 'Default' });

// Render initialized CheckBox.
checkbox.appendTo('#element');

Adding Style sheet to the Application

To render Checkbox component, need to import Button and its dependent components styles as given below in style.css.

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@import "../node_modules/@syncfusion/ej2-base/styles/material.css";
@import "../node_modules/@syncfusion/ej2-buttons/styles/material.css";

Run the application

Run the application in the browser using the following command:

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npm start

The following example shows a basic CheckBox component.

Source
Preview
app.ts
index.html
styles.css
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import { CheckBox } from '@syncfusion/ej2-buttons';
import { enableRipple } from '@syncfusion/ej2-base';

enableRipple(true);

// Initialize CheckBox component.
let checkbox: CheckBox = new CheckBox({ label: 'Default' });

// Render initialized CheckBox.
checkbox.appendTo('#element');
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<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 CheckBox</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript UI Controls" />
    <meta name="author" content="Syncfusion" />
    <link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="styles.css" rel="stylesheet" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
</head>

<body>
    <div id='loader'>LOADING....</div>
    <div id='container'>
        <input type='checkbox' id='element'/>
    </div>
</body>

</html>
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#container {
    visibility: hidden;
}

#loader {
  color: #008cff;
  height: 40px;
  width: 30%;
  position: absolute;
  top: 45%;
  left: 45%;
}

.e-checkbox-wrapper {
  margin-top: 18px;
}

Change the CheckBox state

The Essential JS 2 CheckBox contains 3 different states visually, they are:

  • Checked
  • Unchecked
  • Indeterminate

The CheckBox checked property is used to handle the checked and unchecked state. In checked state a tick mark will be added to the visualization of CheckBox.

Indeterminate

The CheckBox indeterminate state can be set through indeterminate property. CheckBox indeterminate state masks the real value of CheckBox visually. The Checkbox cannot be changed to indeterminate state through the user interface, this state can be achieved only through the property.

Source
Preview
app.ts
index.html
styles.css
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import { CheckBox } from '@syncfusion/ej2-buttons';
import { enableRipple } from '@syncfusion/ej2-base';

enableRipple(true);

//checked state.
let checkbox: CheckBox = new CheckBox({ label: 'Checked State', checked: true });
checkbox.appendTo('#checkbox1');

//unchecked state.
checkbox = new CheckBox({ label: 'Unchecked State' });
checkbox.appendTo('#checkbox2');

//indeterminate state.
checkbox = new CheckBox({ label: 'Indeterminate State', indeterminate: true });
checkbox.appendTo('#checkbox3');
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<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 CheckBox</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript UI Controls" />
    <meta name="author" content="Syncfusion" />
    <link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="styles.css" rel="stylesheet" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
</head>

<body>
    <div id='loader'>LOADING....</div>
    <div id='container'>
        <ul>
            <li><input type="checkbox" id="checkbox1" /></li>
            <li><input type="checkbox" id="checkbox2" /></li>
            <li><input type="checkbox" id="checkbox3" /></li>
        </ul>
    </div>
</body>

</html>
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#container {
    visibility: hidden;
}

#loader {
  color: #008cff;
  height: 40px;
  width: 30%;
  position: absolute;
  top: 45%;
  left: 45%;
}

.e-checkbox-wrapper {
  margin-top: 18px;
}

li {
  list-style: none;
}