1，放在<script></script>标签对之间。
<html> <script language="javascript"> var x = 3; </script> <p>啊哈哈</p> <script language="javascript"> alert(3); </script> </html>
alert(new Date());
<script src="hello.js" language="javascript"> </script>
3,将脚本代码作为属性值
<a href="javascript:alert(new Date());">javascript</a>