struts透过javascript使按钮变灰为不可用，灰色按钮

struts页面用javascript来实现使按钮的变灰

Html代码 ?

1. < html:form ? action = "12.do" ? method = "post" > ??
2. < html:button ? property = "bb" ? onclick = "test();" > 退出 </ html:button > ??
3. </ html:form > ??
4. ??
5. < script ? language = "javascript" ? type = "text/javascript" > ??
6. function?test() ??
7. {??? ??
8. ?document.forms[0] .bb.disabled ???=??? true ???;??? ??
9. } ??
10. </ script > ??

<html:form action="12.do" method="post">
<html:button property="bb" onclick="test();">退出</html:button>
</html:form>

<script language="javascript" type="text/javascript">
function test()
{   
 document.forms[0].bb.disabled   =   true   ;   
}
</script>

?按下这个按钮，他自己就变成灰色且不可点的了