How to Reliably Detect Pre-v9 Internet Explorer Versions in JavaScript?-JS Tutorial-php.cn

How to Reliably Detect Pre-v9 Internet Explorer Versions in JavaScript?

Mary-Kate Olsen

Release： 2024-11-08 14:07:02

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How to Reliably Detect Pre-v9 Internet Explorer Versions in JavaScript?

Detect IE Version (Prior to v9) in JavaScript: A Comprehensive Approach

In this article, we'll explore an alternative approach to detecting pre-v9 Internet Explorer (IE) browsers using JavaScript. While the code provided in the original post may function, it has certain limitations. Let's investigate a more robust solution.

Step 1: Setting Up IE Classes

Our first step is to implement appropriate HTML classes based on the IE versions:

<!DOCTYPE html>
<!--[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]-->
<head>
...

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These classes categorize different IE versions, allowing us to target them using CSS or JavaScript.

Step 2: Detecting IE and Applying JavaScript

Using jQuery, we can create a JavaScript function to recognize old IE browsers and apply the necessary actions:

(function ($) {
    "use strict";

    // Detecting IE
    var oldIE;
    if ($('html').is('.lt-ie7, .lt-ie8, .lt-ie9')) {
        oldIE = true;
    }

    if (oldIE) {
        // Here's your JS for IE..
    } else {
        // ..And here's the full-fat code for everyone else
    }

}(jQuery));

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Addressing Concerns

To address your concerns:

Useragent String Forgery: Even though users can forge their useragent, this approach still provides a reliable indication of IE browser versions.
Feature-Support Sniffing: While feature-support sniffing is generally preferred, it would be inefficient in this case where specific features are already known to be supported or not by different browser versions.
IE Versions 1 or >= 20: Our code intentionally excludes these versions from the "badBrowser" detection, acknowledging the potential risks.
Conditional Comments: IE 10 and later do not support conditional comments, making them an ineffective solution.

Conclusion

This JavaScript-based approach provides a flexible and accurate way to detect pre-v9 IE browsers. By using CSS classes and jQuery, we can seamlessly implement specific actions based on browser versions, ensuring a more consistent user experience.

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