变色的按钮

一个会变色的按钮，很COOL的！！ <style>  .start {color:black; background:red} </style> <script LANGUAGE="JAVASCRIPT">  function highlightButton(s) {   if ("INPUT"==event.srcElement.tagName)    event.srcElement.className=s  } </script> <form name="form2" onmouseover="highlightButton('start')" onmouseout="highlightButton('')"> <center><p> <input type="button" value="按这里试试" name="B2"></p> </form>