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Updated: May 31, 2026
Project Todo
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Conclusion
Project Todo — free browser-based JavaScript (DOM) practice
Why it matters in real projects
This combines reading form values with DOM manipulation. Similar patterns appear daily in code review and production UI work.Step-by-step workflow
1. Read the guide and understand the goal of "Project Todo" 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: addEventListener, appendChild, createElement. 6. After success, continue with adjacent exercises in the same categoryCore concept explained
This combines reading form values with DOM manipulation.Technical focus
Key JavaScript APIs: document.getElementById, document.createElement, addEventListener.Hint before you peek at the solution
createElement, appendChild, valueSample solution walkthrough
JavaScript APIs used: document.getElementById, document.createElement, addEventListener. Verify spelling and async/await usage. Explanation: This combines reading form values with DOM manipulation. Hint recap: createElement, appendChild, valueSolution code
📝 Sample code
document.getElementById('add')?.addEventListener('click', () => {
const input = document.getElementById('todo');
const ul = document.getElementById('list');
if (input?.value && ul) {
const li = document.createElement('li');
li.textContent = input.value;
ul.appendChild(li);
input.value = '';
}
});Common mistakes for this exact task
- Skipping the hint: createElement, appendChild, value - getElementById returns null if the id string differs by even one characterTroubleshooting
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: addEventListener, appendChild, createElement. 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 "Project Todo" 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.getElementById, document.createElement, addEventListenerWhat to do after you pass
Move to the next exercise in the project track, then continue the learning roadmap at /en/learning/project/.Keywords
Free hands-on exercise covering Add a TODO, project, intermediate, document.getElementById, document.createElement, addEventListener, project todo—search-friendly guide for Project Todo.🧪 Try it here — safe to break things
Use the editor below to write code and preview instantly.
Jump to editor■ Exercise task
Write code that adds an li to the ul when the input has a value and the button is clicked.
Hint if stuck
createElement, appendChild, value