DOM Interaction — Complete Guide
DOM Interaction — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of HTML Tutorial on Toolliyo Academy.
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HTML Tutorial · Lesson 63 of 100
DOM Interaction
Basics ✓ → Forms & semantics ✓ → APIs & performance → Projects
APIs & performance · 3 — HTML5, CSS/JS, security · ~10 min · HTML — with CSS & JavaScript
What is this?
DOM APIs let scripts read and update the live HTML tree after load.
Why should you care?
MarkupVerse filters and toggles update lists without server round trips.
See it live — copy this example
Save as demo.html and open in your browser, or use Run Example below.
<ul id="tx-list">
<li data-type="debit">Coffee −₹320</li>
<li data-type="credit">Salary +₹85,000</li>
</ul>
<label><input type="checkbox" id="credits-only"> Credits only</label>
<script>
document.getElementById('credits-only').onchange = e => {
document.querySelectorAll('#tx-list li').forEach(li => {
li.hidden = e.target.checked && li.dataset.type !== 'credit';
});
};
</script>Run Example »
Edit the code below and click Run to see the result in Toolliyo’s live editor.
What happened?
- Prefer hidden attribute over display:none in JS strings.
- data-* holds filter metadata.
Practice next
- Query li nodes.
- Toggle hidden on filter.
- Use data-type for logic.
- Filter debits instead.
- Append a new li with createElement.
Remember
querySelector/querySelectorAll. hidden attribute. data-* for state.
MarkupVerse txn filter
User checks Credits only on banking feed.
Outcome: Debit rows hide instantly.
Interview prep for this lesson
Practice these questions aloud after reading—each links to a full structured answer.
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