JavaScript Navigator platform Property

What You’ll Learn

navigator.platform is a read-only string that identifies the platform the browser is running on. Learn common values, why OS sniffing is unreliable, MDN’s ⌘ vs Ctrl shortcut tip, five examples, and try-it labs.

Introduction

navigator.platform answers a short question: what platform string does the browser report? You might see values such as MacIntel, Win32, or Linux x86_64.

That sounds perfect for OS detection — but MDN warns that using platform (or the user agent) to work around bugs is unreliable. Prefer feature detection for real capability checks.

Understanding the platform Property

Think of platform as a coarse label the browser exposes about its host environment. You read it; you never assign to it.

• String — examples include MacIntel, Win32, Linux x86_64.
• Windows note — modern browsers often return Win32 even on 64-bit Windows.
• Read-only — part of the HTML Navigator interface.
• Baseline — Widely available (MDN, since July 2015).
• Not for sniffing — prefer feature detection for APIs you need.

📝 Syntax

General form of the property:

navigator.platform

Value

• A string indicating a platform.

Common patterns

// Read the string:
console.log(navigator.platform);

// MDN: modifier key hint for shortcuts
const modifierKeyPrefix =
  navigator.platform.startsWith("Mac") || navigator.platform === "iPhone"
    ? "⌘"
    : "Ctrl";

// Prefer this for real features:
if ("serviceWorker" in navigator) {
  // Use Service Workers — do not sniff platform instead
}

Examples Gallery

Examples follow MDN navigator.platform guidance. Prefer Try It Yourself to see your browser’s string.

console.log(navigator.platform);
// Examples: "MacIntel", "Win32", "Linux x86_64"

Win32
(or MacIntel / Linux x86_64 / another platform string)

const modifierKeyPrefix =
  navigator.platform.startsWith("Mac") || navigator.platform === "iPhone"
    ? "⌘" // command key
    : "Ctrl"; // control key

console.log("Save shortcut hint: " + modifierKeyPrefix + "+S");

Save shortcut hint: Ctrl+S
(or ⌘+S on Mac / iPhone platform strings)

const p = navigator.platform;
if (p === "Win32") {
  console.log("Reports Win32 (common even on 64-bit Windows)");
} else {
  console.log("platform: " + p);
}

Reports Win32 (common even on 64-bit Windows)
(or "platform: …" on non-Windows)

const lines = [
  "value: " + navigator.platform,
  "typeof: " + typeof navigator.platform
];
console.log(lines.join("\n"));

value: Win32
typeof: string

const lines = [];
lines.push(
  "platform: " + navigator.platform + " — OK for shortcut labels"
);
lines.push(
  "serviceWorker: " +
    ("serviceWorker" in navigator ? "available" : "missing") +
    " — use this for features"
);
console.log(lines.join("\n"));

platform: Win32 — OK for shortcut labels
serviceWorker: available — use this for features

🚀 Common Use Cases

• Shortcut help text — show ⌘ vs Ctrl in editor / docs UI (MDN pattern).
• Diagnostics — include platform in optional debug panels.
• Learning Navigator — understand classic client-identification strings.
• Not for feature gates — do not enable APIs based on platform alone.
• Not for bitness checks — Win32 is not proof of 32-bit Windows.

📝 Notes

• Baseline Widely available (MDN, since July 2015).
• Not Deprecated, Experimental, or Non-standard — no status banner required.
• Read-only string on Navigator.
• MDN: unreliable for browser / OS sniffing — prefer feature detection.
• On Windows, modern browsers often return Win32 even on 64-bit systems.
• Related: oscpu, appVersion, permissions, Window.

💡 Best Practices