jQuery jQuery.browser Property

What You’ll Learn

The removed jQuery.browser object exposed user-agent flags like msie and webkit plus a version string. This tutorial explains what it was, why jQuery removed it in 1.9, how to read legacy plugins, and what to use instead — feature detection with Modernizr and native APIs.

Introduction

In the early jQuery era, Internet Explorer behaved differently from Firefox, Opera, and early WebKit browsers. Many tutorials branched with if ($.browser.msie) to pick CSS fixes or event workarounds. jQuery shipped jQuery.browser so developers could read those flags without writing their own navigator.userAgent parsers.

The object was available immediately when jQuery loaded — even before $(document).ready() — because it only inspected the user-agent string. That convenience came at a cost: browsers lie, spoof, and change their reported identity. Feature tests proved more reliable than guessing from the UA string.

jQuery deprecated jQuery.browser in version 1.3 and removed it in jQuery 1.9. Modern jQuery 3.x projects should not use it. This page teaches the API so you can maintain legacy code and migrate away from user-agent sniffing.

Understanding the jQuery.browser Property

jQuery.browser is a plain object whose properties are Booleans (except version) derived from navigator.userAgent. The documented flags are:

• msie — Microsoft Internet Explorer
• mozilla — Mozilla-based browsers (Firefox, etc.)
• webkit — WebKit-based browsers (since jQuery 1.4)
• opera — Opera
• safari — deprecated flag; prefer webkit

jQuery.browser.version (added in jQuery 1.1.3) stores a string with the reported rendering engine version — not always the marketing browser version users recognize.

📝 Syntax

Read browser flags and version from the global object:

jQuery.browser
// or
$.browser

// Common legacy checks (jQuery < 1.9 or with Migrate)
$.browser.msie
$.browser.webkit
$.browser.version

Return value

• A plain object with Boolean engine flags and a version string.
• Available synchronously when jQuery loads — no parameters.

Official inspection pattern

jQuery.each( jQuery.browser, function( i, val ) {
  $( "<div>" + i + " : " + val + "</div>" )
    .appendTo( document.body );
});

Examples Gallery

Examples follow the official jQuery.browser documentation. Labs use jQuery 1.12.4 (last 1.x with $.browser) unless noted. jQuery 3.x requires Migrate for these patterns.

jQuery.each( jQuery.browser, function( i, val ) {
  $( "<div>" + i + " : " + val + "</div>" )
    .appendTo( document.body );
});

msie : false
mozilla : true
webkit : true
version : 537.36
...

if ( $.browser.msie ) {
  // IE-specific workaround (legacy)
  $("div.panel").css("zoom", 1);
}

console.log("Is MSIE?", $.browser.msie);

Is MSIE? false (in modern Chrome/Firefox)

if ( $.browser.webkit ) {
  console.log("This is WebKit!");
  $("body").addClass("is-webkit");
}

This is WebKit! (Chrome/Safari/Edge Chromium)
body.is-webkit class added

$("p").html(
  "The version # of the browser's rendering engine is: " +
  $.browser.version
);

if ( $.browser.msie ) {
  console.log("IE engine version:", $.browser.version);
}

The version # of the browser's rendering engine is: 537.36

// jQuery 3.7.1 — $.browser does not exist
console.log(typeof $.browser); // "undefined"

// Replace UA branches with capability checks
var features = {
  flexbox: window.CSS && CSS.supports("display", "flex"),
  grid: window.CSS && CSS.supports("display", "grid"),
  fetch: typeof fetch === "function"
};

if ( features.flexbox ) {
  $("body").addClass("has-flexbox");
}

undefined
has-flexbox class added when supported

🚀 When You Might Encounter jQuery.browser

• Legacy jQuery 1.x plugins — IE or WebKit branches in vendor code.
• Archaeology — understand 2008–2012 tutorials and books.
• Migration audits — grep for $.browser before upgrading jQuery.
• jQuery Migrate — temporary restoration while refactoring sniffing out.
• Not for new features — use Modernizr or native detection.
• Pair with support docs — feature flags vs UA names (jQuery.support).

📝 Notes

• Added jQuery 1.0; deprecated 1.3; removed jQuery 1.9.
• webkit flag added jQuery 1.4; safari flag deprecated.
• jQuery.browser.version added jQuery 1.1.3 — engine version, not always browser marketing version.
• Vulnerable to UA spoofing and compatibility-mode lies (IE8 reporting as 7).
• Restore temporarily via jQuery Migrate when upgrading old sites — then remove branches.
• Related: jQuery.support, Modernizr, CSS.supports().

💡 Best Practices