Always know that use, is every time you use to go to the online copy. Today, I put it down as a note.
1.ie Browser
<!--[If ie]>
<script type= "Text/javascript" > specifically executed scripts </script>
<! [endif]-->
2. Judging ie6,7,8,9
<!--[if IE 7]>
<script type= "Text/javascript" > specifically executed scripts </script>
<! [endif]-->
<!--[if IE 8]>
<script type= "Text/javascript" > specifically executed scripts </script>
<! [endif]-->
<!--[if IE 9]>, other similar
<script type= "Text/javascript" > specifically executed scripts </script>
<! [endif]-->
3. Judging less than IE9, other similar
<!--[If Lt IE 9]>
<script type= "Text/javascript" > Scripts to execute </script>
<! [endif]-->
4. Non-IE9, other similar
<!--[if! Ie9]>
<script type= "Text/javascript" > Other IE scripts performed by non-IE9 </script>
<! [endif]-->
The 5.IE9 version contains IE9
<!--[If LTE IE 9]>
<script type= "Text/javascript" > Scripts to execute </script>
<! [endif]-->
Similar to IE6 more than the version containing IE6
<!--[if GTE IE 6]>
<script type= "Text/javascript" > Scripts to execute </script>
<! [endif]-->
IE Conditional comment