Detect Internet Explorer in JavaScript

JavaScript:

function isIE() {
  return !!window.MSInputMethodContext && !!window.MSInputMethodContext.prototype.createContext;
}

if (isIE()) {
  // User is using Internet Explorer
} else {
  // User is using a different browser
}

In this approach, we check for the presence of the MSInputMethodContext object and its createContext method, which are specific to IE. If both are present, it indicates that the user is using IE.

jQuery:

function isIE() {
  return !!window.MSInputMethodContext && !!window.MSInputMethodContext.prototype.createContext;
}

$(document).ready(function() {
  if (isIE()) {
    // User is using Internet Explorer
    // Do something specific to IE
  } else {
    // User is using a different browser
  }
});

This is essentially the same approach as the JavaScript version, but wrapped within a jQuery document ready function for better integration with jQuery code.

Internet Explorer-specific code:

if (document.documentMode) {
  // User is using Internet Explorer
  var ieVersion = document.documentMode;
  // Do something based on the IE version
} else {
  // User is using a different browser
}

This method leverages the document.documentMode property, which is specific to IE and provides information about the IE version being used.

Key points to remember:

• These methods are generally reliable for detecting IE, but there might be edge cases where they might not work as expected.
• If you need to support older IE versions, you might need to use different detection methods or polyfills.
• It's generally recommended to avoid writing code that relies heavily on IE-specific features. Instead, aim for cross-browser compatibility and use modern JavaScript or libraries that provide feature detection and polyfills.
• Consider using a feature detection library like Modernizr to check for browser support of specific features rather than relying on browser identification.

Method 1: Using MSInputMethodContext

function isIE() {
  return !!window.MSInputMethodContext && !!window.MSInputMethodContext.prototype.createContext;
}

if (isIE()) {
  // User is using Internet Explorer
} else {
  // User is using a different browser
}

• Explanation:
  • The isIE() function checks for the presence of the MSInputMethodContext object, which is specific to IE.
  • It then checks if the createContext method exists on the MSInputMethodContext object.
  • If both conditions are true, it means the user is using IE.

Method 2: Using document.documentMode

if (document.documentMode) {
  // User is using Internet Explorer
  var ieVersion = document.documentMode;
  // Do something based on the IE version
} else {
  // User is using a different browser
}

• Explanation:
  • The document.documentMode property is only available in IE and provides the IE version being used.
  • If this property exists, it indicates that the user is using IE.

Method 3: Using a Feature Detection Library (Modernizr)

if (Modernizr.msie) {
  // User is using Internet Explorer
  var ieVersion = Modernizr.msie;
  // Do something based on the IE version
} else {
  // User is using a different browser
}

• Explanation:
  • Modernizr is a popular JavaScript library that provides feature detection for various browser features.
  • The Modernizr.msie property checks if the browser is IE.

Key Points:

• Reliability: The MSInputMethodContext method is generally considered more reliable for IE detection, especially in older versions.
• IE Version Information: The document.documentMode and Modernizr methods can also provide the IE version being used.
• Feature Detection: Using a feature detection library like Modernizr is often preferred for cross-browser compatibility, as it focuses on detecting specific features rather than identifying the browser itself.

Alternative Methods for Checking IE in JavaScript

While the methods I've previously described are common and reliable, here are some additional approaches you can consider:

User Agent String Analysis

Caution: This method is generally discouraged due to its unreliability and potential for browser spoofing. However, if you're dealing with legacy systems that rely on user agent strings, you can use it as a last resort.

function isIE() {
  return navigator.userAgent.indexOf("MSIE") !== -1 || navigator.userAgent.indexOf("Trident/") !== -1;
}

• Explanation:

Conditional Comments

Note: This method is primarily used for IE-specific CSS styles, but it can also be used for JavaScript code. However, it's not recommended for new development due to its limited compatibility and potential for maintenance issues.

• Explanation:

Third-Party Libraries

Several third-party libraries provide functions for browser detection, including IE. Some popular options include:

These libraries often offer more robust and accurate browser detection capabilities, including information about the IE version and specific features.

Important Considerations:

• Reliability: While these alternative methods can be used in certain scenarios, the MSInputMethodContext and document.documentMode methods are generally considered more reliable and accurate.
• Best Practices: Avoid relying heavily on browser-specific features or detection methods. Aim for cross-browser compatibility and use modern JavaScript and libraries that provide feature detection and polyfills.
• Modernization: If possible, consider modernizing your codebase to avoid the need for IE-specific checks. Focus on using features that are widely supported by modern browsers.