JS Reference
A JavaScript reference is a structured lookup of every built-in object, method, and language feature. Use it as a dictionary while you write code.
What a reference entry typically lists
| Field | Example |
|---|---|
| Signature | Array.prototype.map(callback, thisArg?) |
| Returns | New array — same length, transformed values. |
| Mutates? | No. |
| Since | ES5 (2009). |
| Browser support | Universal. |
Browse the iwantcoding.com reference
- JS Objects Reference — built-in types (Array, String, Number, …).
- HTML DOM Reference — Element, Document, Event, NodeList, …
- Browser Support — what's safe to ship today.
External references worth bookmarking
| Site | Why |
|---|---|
| MDN Web Docs | The most thorough, accurate JS reference on the web. |
| caniuse.com | Per-feature browser support tables, current and historical. |
| TC39 proposals | Track the spec — see what's coming. |
| Node.js / Deno / Bun docs | Server-runtime-specific APIs. |
Tip: Memorise the patterns, look up the exact arguments. Nobody remembers whether
splice is (start, count, …items) or the other order. That's what the reference is for.Example
Example
<!DOCTYPE html>
<html>
<body>
<p id="out"></p>
<script>
document.getElementById("out").textContent = "Hello from JS Reference!";
</script>
</body>
</html>
Try it Yourself »
Exercise
The most thorough external JS reference is…
Answer (three letters):
The Mozilla Developer Network.
Discussion
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