20-1.html

js 全的样例代码,比较适合大家学习和交流

<!-- Set a variable to determine what version of JavaScript we support. -->
<!-- This technique can be extended to any number of language versions. -->
<script language="JavaScript"> var _version = 1.0; </script>
<script language="JavaScript1.1">  _version = 1.1; </script>
<script language="JavaScript1.2">  _version = 1.2; </script>

<!-- Run this code on any JavaScript-enabled browser.  -->
<!-- If the version is not high enough, display a message. -->
<script language="JavaScript">
  if (_version < 1.1) {
    document.write('<hr><h1>This Page Requires JavaScript 1.1</h1>');
    document.write('Your JavaScript 1.0 browser cannot run this page.<hr>');
  }
</script>

<!-- Now run the actual program only on JavaScript 1.1 browsers. -->
<script language="JavaScript1.1">
    // The actual JavaScript 1.1 code goes here.
</script>