input radio 點文字checked

<input type="radio" id="sex1" name="sex" value="M"  /><label for="sex1">male</label>

<input type="radio" id="sex2" name="sex" value="F"  /><label for="sex2">female</label>

參考資料:
http://blog.xuite.net/bluishbox/code/61378093-%5BHTML%5D+%E9%BB%9E%E9%81%B8+radio+%E5%BE%8C%E8%AE%8A%E8%89%B2


http://www.blueshop.com.tw/board/show.asp?subcde=BRD20081001220501J6M



http://pattyshih66.pixnet.net/blog/post/145680918-%E2%92%BF-%E4%BD%BF%E7%94%A8javascript%E5%8F%96%E5%BE%97radio%E5%92%8Cselect%E7%9A%84%E5%80%BC