网页特效代码--复选框全选、全不选和反选的效果实现

<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=gb2312"> <title>网页特效代码--复选框全选、全不选和反选的效果实现</title> <SCRIPT LANGUAGE="JavaScript">  </script> </head> <body> <form name=checkboxform> <input type=checkbox name=C1 checked>C1<br> <input type=checkbox name=C2 checked>C2<br> <input type=checkbox name=C3 checked>C3<br> <input type=checkbox name=C4 checked>C4<br> <input type=checkbox name=C5 checked>C5<br> <input type=checkbox name=C6 checked>C6<br> <input type=checkbox name=C7 checked>C7<br> <input type=checkbox name=C8 checked>C8<br> <input type=checkbox name=C9 checked>C9<br> <br> <input type=button value="全部选中" onClick="checkAll()"><br> <input type=button value="全部不选" onClick="uncheckAll()"><br> <input type=button value="选择转换" onClick="switchAll()"><br> </form> </body> </html>