JavaScript 警告（提示）alert对话框

JavaScript 警告（提示）alert对话框

<html>
   <head>

      <script type = "text/javascript">
         <!--
            function Warn() {
               alert ("This is a warning message!");
               document.write ("This is a warning message!");
            }
         //-->
      </script>

   </head>
   <body>
      <p>Click the following button to see the result: </p>

      <form>
         <input type = "button" value = "Click Me" onclick = "Warn();" />
      </form>

   </body>
</html>