Pen Settings



CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URLs added here will be added as <link>s in order, and before the CSS in the editor. You can use the CSS from another Pen by using its URL and the proper URL extension.

+ add another resource


Babel includes JSX processing.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

+ add another resource


Add Packages

Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.


Auto Save

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

Format on Save

If enabled, your code will be formatted when you actively save your Pen. Note: your code becomes un-folded during formatting.

Editor Settings

Code Indentation

Want to change your Syntax Highlighting theme, Fonts and more?

Visit your global Editor Settings.


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




                function test(x,y) { // function 関数名(引数1,引数2) {処理を書く} 
console.log(x + y);  // x + yを実行してコンソールに出力するという関数
 return x * y;  //関数内で使えるreturn演算子 
//記述したx * yの実行結果を戻り値として返す。(返り値)
 const answer = test(5,6);  //定義した関数を実行する時は 関数名(); と記述する。
//この時点でコンソールには記述された x(5) + y(6)の実行結果 11が出力されている。
//そして、answerには戻り値であるx(5) * y(6)の結果が返っている為