タグ: Javascript

Javascirpt ラジオボタン

index.html

<!DOCTYPE html>
<html lang="ja">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>My JavaScript</title>
</head>
<body>
  <input type="radio" name="color" value="red"> Red
  <input type="radio" name="color" value="green"> Green
  <input type="radio" name="color" value="blue"> Blue
  <button>OK</button>

  <script src="main.js"></script>
</body>
</html>

main.js

'use strict';

{
  document.querySelector('button').addEventListener('click', () => {
    document.querySelectorAll('input').forEach((radio) => {
      if (radio.checked === true) {
        alert(radio.value);
      }
    });
  });
}

Javascirpt ドロップダウンリストの値にアクセス

index.html

<!DOCTYPE html>
<html lang="ja">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>My JavaScript</title>
</head>
<body>
  <select>
    <option value="red">Red</option>
    <option value="green">Green</option>
    <option value="blue">Blue</option>
  </select>
  <button>OK</button>

  <script src="main.js"></script>
</body>
</html>

main.js

'use strict';

{
  document.querySelector('button').addEventListener('click', () => {
    alert(document.querySelector('select').value);
  });
}

Javascirpt フォーム部品の値にアクセス

index.html

<!DOCTYPE html>
<html lang="ja">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>My JavaScript</title>
</head>
<body>
  <!-- <input type="text"> -->
  <textarea></textarea>
  <button>OK</button>

  <script src="main.js"></script>
</body>
</html>

main.js

'use strict';

{
  document.querySelector('button').addEventListener('click', () => {
    // alert(document.querySelector('input').value);
    // alert(document.querySelector('textarea').value);
    document.querySelector('textarea').value = '';
  });
}

Javascript 要素の追加削除

index.html

<!DOCTYPE html>
<html lang="ja">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>My JavaScript</title>
</head>
<body>
  <ul>
    <li class="target">Taro</li>
    <li id="second">Jiro</li>
    <li class="target">Saburo</li>
  </ul>
  <button>OK</button>

  <script src="main.js"></script>
</body>
</html>

main.js

'use strict';

{
  document.querySelector('button').addEventListener('click', () => {
    const liElement = document.createElement('li');
    liElement.textContent = 'Hanako';
    // document.querySelector('ul').appendChild(liElement);
    // document.querySelector('ul').insertBefore(
    //   liElement, 
    //   document.querySelector('#second')
    // );
    if (confirm('Sure?') === true) {
      document.querySelector('#second').remove();
    }
  });
}

Javascirpt createElement

index.html

<!DOCTYPE html>
<html lang="ja">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>My JavaScript</title>
</head>
<body>
  <ul>
    <li class="target">Taro</li>
    <li id="second">Jiro</li>
    <li class="target">Saburo</li>
  </ul>
  <button>OK</button>

  <script src="main.js"></script>
</body>
</html>

main.js

'use strict';

{
  document.querySelector('button').addEventListener('click', () => {
    const liElement = document.createElement('li');
    liElement.textContent = 'Hanako';
  });
}

Javascript classList

index.html

<!DOCTYPE html>
<html lang="ja">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>My JavaScript</title>
  <style>
    .pink-bg{
      background: pink;
    }

    .red-border{
      border: 2px solid red;
    }

    .green-color{
      color: green;
    }
  </style>
</head>
<body>
  <p>Hello</p>
  <button>OK</button>
  
  <script src="main.js"></script>
</body>
</html>

main.js

'use strict'

{
    document.querySelector('button').addEventListener('click', ()=> {
        //console.log('Clicked');
        document.querySelector('p').classList.add('pink-bg', 'red-border');
        document.querySelector('p').classList.add('green-color');
    });

    //console.log('Hello');
}

Javascript イベントリスナー

index.html

<!DOCTYPE html>
<html lang="ja">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>My JavaScript</title>
</head>
<body>
  <button>OK</button>
  
  <script src="main.js"></script>
</body>
</html>

main.js

'use strict';

{
  document.querySelector('button').addEventListener('click', () => {
    console.log('Clicked');
  });
}

Javascript スプレッド構文

index.html

<!DOCTYPE html>
<html lang="ja">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>My JavaScript</title>
</head>
<body>
  <script src="main.js"></script>
</body>
</html>

main.js

'use strict';

{
  const moreScores = [77, 88];
  const scores = [70,90,80,85, ...oreScores];
  const [first, ...others] = scores;

  console.log(first);
  console.log(others);
}

Javasript 分割代入

index.html

<!DOCTYPE html>
<html lang="ja">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>My JavaScript</title>
</head>
<body>
  <script src="main.js"></script>
</body>
</html>

main.js

'use strict';

{
let start = 'Tokyo';
let goal = 'Osaka';

//start = goal;
//goal = start;

//let temp = "";
//temp = start;
//start = goal;
//goal = temp;

[goal, start] = [start, goal]

console.log(start);
console.log(goal);
}

Javascript 分割代入

index.html

<!DOCTYPE html>
<html lang="ja">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>My JavaScript</title>
</head>
<body>
  <script src="main.js"></script>
</body>
</html>

main.js

'use strict';

{
  const scores = [70, 90, 80, 85];
  // const first = scores[0];
  // const second = scores[1];
  // const third = scores[2];
  // const fourth = scores[3];
  const [first, second, third, fourth] = scores;

  console.log(first);
  console.log(second);
  console.log(third);
  console.log(fourth);
}