检测浏览器当前Javascript版本
<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 type="text/javascript">
document.write('<p><b>Javascript version ' + jsver
+ ' supported<\/b><\/p>');
</script>