November 2021
Intermediate to advanced
256 pages
6h 17m
Japanese
Content preview from つくって楽しいJavaScript入門 身近な不思議をプログラミングしてみよう
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エラーの種類と表示
主なエラーは、「構文エラー」と「参照エラー」の 2 つです。
構文エラーはプログラムの構文（文法）上の誤りがあるときに出ます。先ほどの例のように、括
弧の種類を間違えたりした場合です。
日本語の文章でも、句読点が抜けていたり、括弧の対応が取れていなかったりすると、読んでい
て「あれっ？ 意味がわからないぞ！」となりますよね？ それと同じです。
一方、参照エラーは、コンピューターが、入力された文字を何かの「名前」だと思ったのに、そ
んな名前の「もの」は見つからなかった、というときに出ます。ようするに、名前を打ち間違えた
ということです。
エラーはコンソール出力に日本語で表示されます（図 1-8）。数字はエラーが発生したのが何行
目の［何桁目］なのかを表し、クリックするとその行にジャンプします。
プログラミングしていると、エラーはたくさん出るものです。そんなときは、落ち着いて、エ
ラーがあると言われた行のあたりをよく確認しましょう。
図 1-8
Croqujs のエラー表示
Column
全角と半角
プログラムを入力するときは、漢字変換機能がOFFになっていることを確認しましょう。例えば、半角
スペースの代わりに全角スペースを入力するとエラーになります。
エラーが出てもガーン
と思わない！ 間違い
を教えてくれたんだか
ら、ありがたいね！
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.