IE 8的条件注释不起作用

Question

I'm trying to change the SRC attribute of my iFrame for users on IE 8 or less.

Here's my code :

  <script>
var i_am_old_ie = false;
<!--[if lte IE 8]>
i_am_old_ie = true;
<![endif]-->
</script>
    <script type="text/javascript">
    $(document).ready(function() {
if(i_am_old_ie) {
   $("#shop").attr("src","shopping_cart/browser_support.html"); 
} else {
    $("#shop").attr("src","shopping_cart/index.html"); 
}      
});
</script>

It detects that it's IE...but still sends all IE users to shopping_cart/browser_support.html . Even if I use IE 9, it will send me there. Same thing for 7, or 8.

But it sends all other users not using IE to shopping_cart/index.html (wich is correct).

What's wrong in my code?

Thank you!

Answer 1

You can't insert the inside the script tag. It needs to be outside.

<script>
var i_am_old_ie = false;
</script>

<!--[if lte IE 8]>

<script>
i_am_old_ie = true;
</script>
<![endif]-->

Answer 2

As others mentioned you can not use HTML conditional statements between <script> tags.

This should work however:

if (document.all && !document.getElementsByClassName) {
    i_am_old_ie = true;
}

The above will only run in IE8 or below

Edit:

Some nice examples LINK

Answer 3

There is a different syntax for conditional comments inside JavaScript. What does @cc_on mean in JavaScript? has details.

Wikipedia's Conditional comment page has an example of version switching using it.

 <script> /*@cc_on @if (@_jscript_version == 10) document.write("You are using IE10"); @elif (@_jscript_version == 9) document.write("You are using IE9"); @elif (@_jscript_version == 5.8) document.write("You are using IE8"); @elif (@_jscript_version == 5.7 && window.XMLHttpRequest) document.write("You are using IE7"); @elif (@_jscript_version == 5.6 || (@_jscript_version == 5.7 && !window.XMLHttpRequest)) document.write("You are using IE6"); @elif (@_jscript_version == 5.5) document.write("You are using IE5.5"); @else document.write("You are using IE5 or older"); @end @*/ </script> 

Answer 4

Conditional HTML comments only work in HTML.

JavaScript is not HTML.

It's generally not a good idea, and feature detection is reccomended, but if using jQuery you can do:

var i_am_old_ie = $.browser.msie && ($.browser.version <= 8);