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Is Using `navigator.appName` and `navigator.appVersion` Reliable for Detecting Older IE Versions?

Mary-Kate Olsen
Mary-Kate OlsenOriginal
2024-11-06 14:54:02900browse

Is Using `navigator.appName` and `navigator.appVersion` Reliable for Detecting Older IE Versions?

Detect IE Version (Prior to v9) in JavaScript

Detection Criteria and Proposed Code

To determine if a user is accessing a website using a version of Internet Explorer prior to v9, the proposed code leverages the navigator.appName and navigator.appVersion properties.

if (navigator.appName.indexOf("Internet Explorer") != -1) {
    // User is using IE
    // Check for IE version < 9
}

Will This Code Do the Trick?

Despite addressing the concerns raised about user agent string spoofing and feature support detection, the proposed code has several limitations:

  • Conditional statements: While conditional statements are useful for targeting different IE versions, they are only supported in IE5-9, so this approach is obsolete in modern browsers.
  • Precision (IE 1 and IE 10 ): The code fails to detect IE 1 and IE versions greater than or equal to 10.
  • Completeness: The code only checks for IE versions less than 9, ignoring potential edge cases.

A Preferred Alternative

To overcome these limitations, a more comprehensive approach involves using CSS class-based detection:

  1. Define CSS classes that represent different IE versions, e.g.:
html.lt-ie9 { ... }
html.lt-ie8 { ... }
html.lt-ie7 { ... }
  1. Apply these classes to the element based on the detected IE version:
    <!--[if lt IE 7]> <html class="lt-ie9 lt-ie8 lt-ie7"> <![endif]-->
    <!--[if IE 7]>    <html class="lt-ie9 lt-ie8"> <![endif]-->
    <!--[if IE 8]>    <html class="lt-ie9"> <![endif]-->
    <!--[if gt IE 8]><!--> <html> <!--<![endif]-->
    1. Use CSS to specify styles specific to the detected IE version, or implement JavaScript logic based on the assigned class:
    if ($('html').is('.lt-ie7, .lt-ie8, .lt-ie9')) {
        // IE version < 9
    } else {
        // Other browsers
    }

    This method provides more flexibility, compatibility, and control for handling different browser versions.

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