JavaScript - Browser - Handling Events(Censored Keyboard, keydown, keyCode, preventDefault)

Eloquent JavaScript

開発環境

• macOS Sierra - Apple (OS)
• Emacs (Text Editor)
• JavaScript (プログラミング言語)
• Safari、Firefox(Web browser)

Eloquent JavaScript(Marijn Haverbeke 著、No Starch Press)のPart 2(Browser)、Chapter 14(Handling Events)、Exercises(Censored Keyboard)を取り組んでみる。

Exercises(Censored Keyboard)

コード(Emacs)

HTML5

<input id="text0" type="text"></input>
<script src="sample1.js"></script>

JavaScript

'use strict';
let input_text = document.querySelector('#text0');

input_text.addEventListener('keydown', (event) => {
    let keyCode = event.keyCode;
    if (keyCode === 81 || keyCode === 87 || keyCode === 88) {
        event.preventDefault();
    }
});