I'm just reading this documentation about Javascript 1.2, but I'm wondering which version of Javascript is being used in the most popular browsers.
http://www.tutorialspoint.com/javascript/javascript_nested_functions.htm
Click on this link to see which version your BROWSER is using: http://jsfiddle.net/Ac6CT/
You should be able filter by using script tags to each JS version.
<script type="text/javascript">
var jsver = 1.0;
</script>
<script language="Javascript1.1">
jsver = 1.1;
</script>
<script language="Javascript1.2">
jsver = 1.2;
</script>
<script language="Javascript1.3">
jsver = 1.3;
</script>
<script language="Javascript1.4">
jsver = 1.4;
</script>
<script language="Javascript1.5">
jsver = 1.5;
</script>
<script language="Javascript1.6">
jsver = 1.6;
</script>
<script language="Javascript1.7">
jsver = 1.7;
</script>
<script language="Javascript1.8">
jsver = 1.8;
</script>
<script language="Javascript1.9">
jsver = 1.9;
</script>
<script type="text/javascript">
alert(jsver);
</script>
My Chrome reports 1.7
Blatantly stolen from: http://javascript.about.com/library/bljver.htm