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How to include a js file for a different version of jquery (one that supports IE8)?

I have a simple webpage, it is just some css and html. I need to include mobile nav using jquery and it also needs to be compatible with IE8.
I found out that IE8 supports version 1.1.9 of jquery and I also found how to use these different version depending in which browser my site is loaded.
My question is do I need to also include in my html in script tag different js file that will be run if I use jquery version for IE8? Thank you for all of your answers
//this is what i have - before </body>
<!--[if lt IE 9]>
<script src="https://code.jquery.com/jquery-1.9.0.min.js"</script>
<![endif]-->
<!--[if gte IE 9]><!-->
<script src="https://code.jquery.com/jquery-3.4.0.min.js"></script>
<!--<![endif]-->
//and how do I render my js file with my code? is it like this?
<!--[if lt IE 9]>
<script src="https://code.jquery.com/jquery-1.9.0.min.js"</script>
<script src="app1.js"</script>
<![endif]-->
<!--[if gte IE 9]><!-->
<script src="app2.js"></script>
<!--<![endif]-->

I will try to clarify your question in this answer.
You can conditionally include HTML code based for IE (as you have shown). The conditions do not provide scope, so you needn't respecify tags which you have already included. However, for Javascript, you will need to include the dependent files before you refer to them. So, if you are including the jquery before the closing </body> then you should include your code after it.
<!--[if lt IE 9]>
<script src="https://code.jquery.com/jquery-1.9.0.min.js"</script>
<script src="app1.js"</script>
<![endif]-->
<!--[if gte IE 9]>
<script src="https://code.jquery.com/jquery-3.4.0.min.js"></script>
<script src="app2.js"></script>
<![endif]-->
</body>
If you need to separate the inclusion of jquery from the inclusion of our own code, you needn't respecify the jquery inclusion:
<!--[if lt IE 9]>
<script src="https://code.jquery.com/jquery-1.9.0.min.js"</script>
<![endif]-->
<!--[if gte IE 9]>
<script src="https://code.jquery.com/jquery-3.4.0.min.js"></script>
<![endif]-->
... other stuff here ...
<!--[if lt IE 9]>
<script src="app1.js"</script>
<![endif]-->
<!--[if gte IE 9]>
<script src="app2.js"></script>
<![endif]-->
</body>
Note that in these examples, you are not including jquery for non-IE browsers. If the support for IE > 9 is the same as for other browsers, then you can have the tags be included for non-IE browsers as well. The following, I use the consolidated example, at the top:
<!--[if lt IE 9]>
<script src="https://code.jquery.com/jquery-1.9.0.min.js"</script>
<script src="app1.js"</script>
<![endif]-->
<!--[if gte IE 9]><!-->
<script src="https://code.jquery.com/jquery-3.4.0.min.js"></script>
<script src="app2.js"></script>
<!--<![endif]-->
</body>
Note that the conditional tags are actually commented out, from the point of view of non-IE browsers.

Conditional comments alternative to load jQuery

Because jQuery 2+ doesn't support IE 8, I'll need to make use of a previous version: jQuery 1.9.
Is there a way to include jQuery 1.9 when using IE <= 8 and jQuery 2+ when using IE > 8.
I tried it with Conditional comments:
<!--[if lt IE 9]><!--><script> .. googleapis jquery 1.9 .. </script><!--<![endif]-->
<!--[if gte IE 9]><!--><script> .. googleapis jquery 2+ .. </script><!--<![endif]-->
The problem is that It is not working and I found some information about it not being supported anymore: http://msdn.microsoft.com/en-us/library/ie/hh801214(v=vs.85).aspx
Is there another way?

You want the IE8 version to be in a commented-out block, but the non-IE9 version not to be:
<!--[if lt IE 9]> <script> .. googleapis jquery 1.9 .. </script> <![endif]-->
<![if !IE|gte IE 9]> <script> .. googleapis jquery 2+ .. </script> <![endif]>
Live Example with alerts
IE8 recognizes conditional comments, but other browsers don't (including newer IEs).
You also probably want to have !IE in the second one, just for completeness, as above.

This will serve a different version of jQuery to Internet Explorer versions 6-8:
<!--[if lt IE 9]>
<script src="jquery-1.9.0.js"></script>
<![endif]-->
<!--[if gte IE 9]><!-->
<script src="jquery-2.0.0.js"></script>
<!--<![endif]-->
or the somewhat easier to read (but functionally identical):
<!--[if lt IE 9]>
<script src="jquery-1.9.0.js"></script>
<![endif]-->
<!--[if (gte IE 9) | (!IE)]><!-->
<script src="jquery-2.0.0.js"></script>
<!--<![endif]-->

Bravo to T.J. Crowder (above) for his answer. This one racked my brain, I was having some trouble as IE8 was loading both JQuery files at times or the script I wrote would not allow JQuery to fire afterward due to the way the document was loading. One addition to the above answer, I actually had to reverse the order of the two conditionals in order to ensure more than one copy of JQuery was not loading in IE8.
<![if !IE|gte IE 9]> <script src="http://code.jquery.com/jquery-2.1.1.min.js"></script> <![endif]>
<!--[if lt IE 9]> <script src="http://code.jquery.com/jquery-1.11.0.min.js"></script> <![endif]-->

You could check the UserAgentString on server code, and include one or another depending on it.
Here is a list of Internet Explorer User Agents:http://www.useragentstring.com/pages/Internet%20Explorer/

Using conditional comments with RequireJS to load IE7/8 only jQuery

I'm using Require JS in my project which is loading jQuery and some other JavaScript files that are relevant for the entire site and all browsers.
However, I need to use some conditional jQuery on Internet Explorer 7 & 8, I've tried putting this in the head of the page and the script doesn't seem to be able to find jQuery, I'm presuming this is because it's getting loaded before jQuery.
<script data-main="/#ViewBag.ScriptsFolder/main" src="/scripts/require.js" type="text/javascript"></script>
<!--[if (gte IE 6)&(lte IE 8)]>
<script type="text/javascript" src="/Scripts/ie.js"></script>
<![endif]-->
Is there any way to rectify this? I'm also trying to load Selectivizr in this way which isn't working because of the same problem.
Thanks

You could use a conditional IE-specific class on the html element, then checking for it and loading the IE dependencies inside your existing main script. So, the top of the document would look like:
<!--[if lt IE 7]> <html class="ie lt-ie9 lt-ie8 lt-ie7"> <![endif]-->
<!--[if IE 7]> <html class="ie lt-ie9 lt-ie8"> <![endif]-->
<!--[if IE 8]> <html class="ie lt-ie9"> <![endif]-->
<!--[if gt IE 8]> <html class="ie"> <![endif]-->
<html>
And then inside main.js, you could use:
if ($('html.lt-ie9').size()) {
require(['/Scripts/ie'], function(ieScript) {
// ... do stuff
});
}
You can't use the method you've described because require.js looks for a single data-main attribute to specify the 'entry point' - any subsequent calls to require should be done in Javascript.

How not to load a script in IE?

It's possible to load a script only in IE with conditional comments
<!--[if lte IE 7]>
<script type="text/javascript" src="somescript.js"></script>
<![endif]-->
but what if I don't want to load it in IE lte 7 (but still need it in all other browsers)?
Any simple solutions?
P.S. I have a problem with SyntaxHighlighter - too many code slows IE7 down and since I'm short of time, I decided just to turn it off in IE7 for now.

This post says you can use the ! (NOT) operator like [if !IE]

<![if !IE]>
<script type="text/javascript" src="somescript.js"></script>
<![endif]>

<!--[if gte IE 7]>
<script type="text/javascript" src="somescript.js"></script>
<![endif]-->
<!--[if !IE]>
<script type="text/javascript" src="somescript.js"></script>
<![endif]-->

This syntax works good (the script wouldn't be commented in firefox, chrome and so on):
<!--[if !IE]><!-->
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
<!--<![endif]-->

You could try detecting the browser server-side and then echo the appropriate script includes.
The following has an example on simplistic browser detection in PHP:
http://www.php-scripts.com/20050912/12/

Since conditional statements are not Working in IE (10,11) and only IE(11) is supported by Microsoft and if anyone is still looking at running IE specific JavaScript then this code still works tested in IE(11), and non IE browsers(Chrome,Firefox,Edge).
<script type="text/javascript">
if(/MSIE \d|Trident.*rv:/.test(navigator.userAgent))
{document.write('<script src="../nolng/js/ex1IE.js"><\/script>');}
else
{document.write('<script src="../nolng/js/ex1.js"><\/script>'); // for Chrome,Firefox,Edge}
</script>

I used the examples shown here and elsewhere, and it is really frustrating to see how many places this code example is messed up. Turns out the answer is simple, IE has special 'conditionals' like [if IE], but other browsers need comments to work with the 'conditionals'.
For example, since JQuery 2 doesn't work with IE8, you can do something like this
<!--[if IE ]> (following is only visible to IE)
<script src="./js/lib/jquery-1.6.1.min.js"></script>
<![endif]-->
<!--[if !IE]>--> (extra comment - only visible to non-IE)
<script src="./js/lib/jquery-2.1.1.min.js"></script>
<script src="./js/lib/jquery.mobile-1.4.5.min.js"></script>
<!--<![endif]-->
I have verified the above works in Firefox, Chrome, IE8, Dolphin mobile, and Chrome mobile. You can also specify version. For example, less than IE 9 would be: <!--[if lt IE 9 ]>
For a detailed explanation, check out http://www.sitepoint.com/web-foundations/internet-explorer-conditional-comments/

How can I deal with the following error I get when I use Dean Edwards' IE7.js with IE6?

I'm using Dean Edwards' IE7.js for IE6
<!--[if lt IE 7]>
<script src="http://ie7-js.googlecode.com/svn/version/2.0(beta3)/IE7.js"
type="text/javascript"></script>
<![endif]-->
and getting a JavaScript error on IE 6 when it reads the line:
c.runtimeStyle[h]=c.parentElement.currentStyle[h]
How can I solve this?

I don't believe IE6 has a parentElement property. You might be able to get around this by including this code in the <!--[if lt ie7]> tag:
Element.prototype.parentElement = Element.prototype.parentNode;