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Updated: 2026年5月31日

Dom Query Selector All

Original task (JA): 全要素を取得

📌

Conclusion

Dom Query Selector All — free browser-based JavaScript (DOM) practice

■ What this exercise teaches idが「list」のul内の全liを取得し、それぞれのtextContentをconsole.logで出力してください。

Why it matters in real projects

querySelectorAllで該当する全要素を取得。forEachでループ。 Similar patterns appear daily in code review and production UI work.

Step-by-step workflow

1. Read the guide and understand the goal of "Dom Query Selector All" 2. Review the JavaScript (DOM) editor pane and start from the starter code 3. Open hints if stuck; compare your diff with the sample solution 4. Click Run and inspect preview/console output 5. Auto-check looks for output containing: 項目1, 項目2. 6. After success, continue with adjacent exercises in the same category

Core concept explained

querySelectorAllで該当する全要素を取得。forEachでループ。

Technical focus

Key JavaScript APIs: document.querySelectorAll, console.log.

Hint before you peek at the solution

querySelectorAll('#list li')、forEach

Sample solution walkthrough

JavaScript APIs used: document.querySelectorAll, console.log. Verify spelling and async/await usage. Explanation: querySelectorAllで該当する全要素を取得。forEachでループ。 Hint recap: querySelectorAll('#list li')、forEach

Solution code

📝 Sample code
document.querySelectorAll('#list li').forEach(el => {
  console.log(el.textContent);
});

Common mistakes for this exact task

・Skipping the hint: querySelectorAll('#list li')、forEach

Troubleshooting

Q: Preview does not change after Run A: Ensure you edited the JavaScript (DOM) pane and clicked Run. Q: Looks correct but check fails A: Auto-check looks for output containing: 項目1, 項目2. Look for typos, full-width spaces, or unclosed tags. Q: Console shows errors A: Open DevTools Console and fix bracket/quote mismatches at the reported line. Q: Hard to type on mobile A: Use landscape mode or continue on desktop—the same URL keeps progress in localStorage.

Interview / portfolio tips

・Explain the techniques in "Dom Query Selector All" in your own words within 30 seconds ・Practice walking through each line of the sample solution on a whiteboard ・Connect this task to a real component you would ship ・Mention responsive or accessibility trade-offs ・Describe when you use: document.querySelectorAll, console.log

What to do after you pass

Move to the next exercise in the dom track, then continue the learning roadmap at /en/learning/js-basic/.

Keywords

Free hands-on exercise covering 全要素を取得, dom, 中級, document.querySelectorAll, console.log, dom query selector all—search-friendly guide for Dom Query Selector All.

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■ Exercise task

idが「list」のul内の全liを取得し、それぞれのtextContentをconsole.logで出力してください。

Hint if stuck

querySelectorAll('#list li')、forEach

20pt

全要素を取得

idがlistのul内の全liを取得し、それぞれのtextContentをconsole.logで出力してください。

エラーをクリックで該当行をハイライト。✕=エラー ⚠=警告 ›=ログ。

Roadmap · All guides

Deep dive

"Dom Query Selector All" is a 中級-level JavaScript (DOM) exercise. idが「list」のul内の全liを取得し、それぞれのtextContentをconsole.logで出力してください。 Run it in-browser with automatic checking.

querySelectorAllで該当する全要素を取得。forEachでループ。 Similar patterns appear daily in code review and production UI work.

Pair this with the js-basic roadmap. Exercise #59 reinforces core dom skills.

Step-by-step workflow

  1. Read the guide and understand the goal of "Dom Query Selector All"
  2. Review the JavaScript (DOM) editor pane and start from the starter code
  3. Open hints if stuck; compare your diff with the sample solution
  4. Click Run and inspect preview/console output
  5. Auto-check looks for output containing: 項目1, 項目2.
  6. After success, continue with adjacent exercises in the same category

How to read the sample solution

JavaScript APIs used: document.querySelectorAll, console.log. Verify spelling and async/await usage. Explanation: querySelectorAllで該当する全要素を取得。forEachでループ。 Hint recap: querySelectorAll('#list li')、forEach

Real-world & career relevance

DOM APIs power clicks, forms, and modals—from jQuery era to modern SPAs.

Common mistakes

  • Skipping the hint: querySelectorAll('#list li')、forEach
  • Typo in getElementById
  • Using onClick instead of addEventListener
  • Setting textContent without null check

Troubleshooting

Preview does not change after Run
Ensure you edited the JavaScript (DOM) pane and clicked Run.
Looks correct but check fails
Auto-check looks for output containing: 項目1, 項目2. Look for typos, full-width spaces, or unclosed tags.
Console shows errors
Open DevTools Console and fix bracket/quote mismatches at the reported line.
Hard to type on mobile
Use landscape mode or continue on desktop—the same URL keeps progress in localStorage.

Interview & portfolio tips

  • Explain the techniques in "Dom Query Selector All" in your own words within 30 seconds
  • Practice walking through each line of the sample solution on a whiteboard
  • Connect this task to a real component you would ship
  • Mention responsive or accessibility trade-offs
  • Describe when you use: document.querySelectorAll, console.log

Glossary

DOM
Document Object Model—tree API for HTML.
getElementById
Fetch one element by id.
addEventListener
Register click and other events.

Keywords covered on this page

Free hands-on exercise covering 全要素を取得, dom, 中級, document.querySelectorAll, console.log, dom query selector all—search-friendly guide for Dom Query Selector All.

Related dev tools

Learning roadmap

Learning roadmap →

Related exercises

Frequently asked questions

Is "全要素を取得" free?

This exercise is free and runs entirely in your browser. No account or credit card required.

Difficulty and time?

"全要素を取得" is level "中級". Read the guide first; beginners can usually finish within 30 minutes. Allow 5–15 minutes per exercise. Use hints, then the solution if stuck.

What after a correct answer?

After a correct answer, use "Next exercise". When you finish a category, continue on the learning roadmap.

Works on mobile?

Works on mobile browsers, but typing code is easier on a desktop.

Where are other exercises?

All exercises: /en/learn/ with category filters.

Key takeaway for "全要素を取得"?

querySelectorAllで該当する全要素を取得。forEachでループ。 Hint: querySelectorAll('#list li')、forEach

Where does dom fit?

DOM APIs power clicks, forms, and modals—from jQuery era to modern SPAs.

Step-by-step for "Dom Query Selector All"?

1. Read the guide and understand the goal of "Dom Query Selector All"
2. Review the JavaScript (DOM) editor pane and start from the starter code
3. Open hints if stuck; compare your diff with the sample solution
4. Click Run and inspect preview/console output
5. Auto-check looks for output containing: 項目1, 項目2.
6. After success, continue with adjacent exercises in the same category

How to read the sample solution?

JavaScript APIs used: document.querySelectorAll, console.log. Verify spelling and async/await usage.

Explanation: querySelectorAllで該当する全要素を取得。forEachでループ。

Hint recap: querySelectorAll('#list li')、forEach

Something is not working?

Preview does not change after Run → Ensure you edited the JavaScript (DOM) pane and clicked Run.
Looks correct but check fails → Auto-check looks for output containing: 項目1, 項目2. Look for typos, full-width spaces, or unclosed tags.
Console shows errors → Open DevTools Console and fix bracket/quote mismatches at the reported line.
Hard to type on mobile → Use landscape mode or continue on desktop—the same URL keeps progress in localStorage.

Career / interview angle?

Explain the techniques in "Dom Query Selector All" in your own words within 30 seconds Practice walking through each line of the sample solution on a whiteboard Connect this task to a real component you would ship Mention responsive or accessibility trade-offs Describe when you use: document.querySelectorAll, console.log

Can I change the starter code?

Yes—if it works. Understanding the starter first, then adding minimal diffs, speeds up learning.

What do the points mean?

20pt is a difficulty hint, not a score you must maximize.