代码如下：
<SCRIPT LANGUAGE="JavaScript"> <!-- Begin function checkAll() { for (var j = 1; j <= 9; j++) { box = eval("document.checkboxform.C" + j); if (box.checked == false) box.checked = true; } } function uncheckAll() { for (var j = 1; j <= 9; j++) { box = eval("document.checkboxform.C" + j); if (box.checked == true) box.checked = false; } } function switchAll() { for (var j = 1; j <= 9; j++) { box = eval("document.checkboxform.C" + j); box.checked = !box.checked; } } // End --> </script> <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>