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I want a piece of Javascript to run if the browser is not IE or it is IE 9+. If the browser is IE8 or a lower version, another piece of Javascript should run.

I tried to use Conditional Comments:

<!--[if (!IE)|(gte IE 9)]>
    <script type="text/javascript"> /* code 1 */ </script>
<![endif]-->

<!--[if (lt IE 9)]>
    <script type="text/javascript"> /* code 2 */ </script>
<![endif]-->

But IE6 and IE7 still were executing code 1. And Firefox was executing code 2...

No jQuery, please.

Edit: Actually, my conditional expression was wrong. But still went with the feature detection proposed in the chosen answer.

I want a piece of Javascript to run if the browser is not IE or it is IE 9+. If the browser is IE8 or a lower version, another piece of Javascript should run.

I tried to use Conditional Comments:

<!--[if (!IE)|(gte IE 9)]>
    <script type="text/javascript"> /* code 1 */ </script>
<![endif]-->

<!--[if (lt IE 9)]>
    <script type="text/javascript"> /* code 2 */ </script>
<![endif]-->

But IE6 and IE7 still were executing code 1. And Firefox was executing code 2...

No jQuery, please.

Edit: Actually, my conditional expression was wrong. But still went with the feature detection proposed in the chosen answer.

• javascript
• html
• internet-explorer

Share Improve this question Follow edited Sep 23, 2012 at 15:47 John Assymptoth asked Sep 21, 2012 at 18:55 John AssymptothJohn Assymptoth 8,5171212 gold badges5353 silver badges6969 bronze badges 2

• 4 It is generally much, much better to do feature detection than browser detection. So, if you describe what feature you want to use in IE9 and other browsers, but not in IE8 and below, then you can use a run-time feature detection which generally is more accurate than browser detection. – jfriend00 Commented Sep 21, 2012 at 19:04
• I want to use document.getElementByClass(), which is only available in IE8+ – John Assymptoth Commented Sep 21, 2012 at 21:08

Add a ment  | 

3 Answers 3

Sorted by: Reset to default 5

From your ment, it sounds like you're just trying to decide if you can use document.getElementsByClassName(). If that's the case, you can use feature detection like this:

if (document.getElementsByClassName) {
    // code here that uses getElementsByClassName
} else {
    // code here that doesn't use getElementsByClassName
}

---

It may be cleaner to just install a polyfill so that you can use it in older versions of IE without having to check first. There are a number of them available you can find with a Google search. Here's one:

// Add a getElementsByClassName function if the browser doesn't have one
// Limitation: only works with one class name
// Copyright: Eike Send http://eike.se/nd
// License: MIT License

if (!document.getElementsByClassName) {
  document.getElementsByClassName = function(search) {
    var d = document, elements, pattern, i, results = [];
    if (d.querySelectorAll) { // IE8
      return d.querySelectorAll("." + search);
    }
    if (d.evaluate) { // IE6, IE7
      pattern = ".//*[contains(concat(' ', @class, ' '), ' " + search + " ')]";
      elements = d.evaluate(pattern, d, null, 0, null);
      while ((i = elements.iterateNext())) {
        results.push(i);
      }
    } else {
      elements = d.getElementsByTagName("*");
      pattern = new RegExp("(^|\\s)" + search + "(\\s|$)");
      for (i = 0; i < elements.length; i++) {
        if ( pattern.test(elements[i].className) ) {
          results.push(elements[i]);
        }
      }
    }
    return results;
  }
}

You can do this best by a check within javascript instead of one in HTML. In JS you have the property navigator.userAgent which returns a unique string for each browser (and even IE in its different patibility versions). So I would suggest to execute the whole JS block in all browsers and simply add something like this add the top of it:

if(navigator.userAgent.indexOf('MSIE 9.0') !== -1)
{
  // call IE9 specific method
}
else
{
  // call method for other browsers
}

For a more sophisticated approach see this post navigator.userAgent

As jfriend00 states feature detection may be a better solution but here is the conditional ments that satisfy your requirements.

<!--[if gte IE 9]> -->
    <script type="text/javascript"> alert('ie9+ and not ie') </script>
<!-- <![endif]-->
<!--[if lt IE 9]>
    <script type="text/javascript"> alert(' < ie9') </script>
<![endif]-->

http://jsfiddle/szF4J/1/

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