代码：
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>全选与全不选</title> <script> function checkAll() { //获得当前第一个checkbox的状态 var check_1 = document.getElementById("check_1"); //得到当前checked状态 var checked = check_1.checked; //获得所有分类项的checkbox var checks = document.getElementsByName("checkone"); for (var i = 0; i < checks.length; i++) { //修改每一个checkbox的状态 var checkone = checks[i]; checkone.checked = checked; } } </script> </head> <body onload="init()"> <table border="1px" id="tab"> <thead> <tr> <th> <input type="checkbox" onclick="checkAll()" id="check_1"/> </th> <th>全选与全不选</th> </tr> </thead> <tbody> <tr> <td> <input type="checkbox" name="checkone"/> </td> </tr> <tr> <td> <input type="checkbox" name="checkone"/> </td> </tr> <tr> <td> <input type="checkbox" name="checkone"/> </td> </tr> </tbody> </table> </body> </html>