<!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <meta name="viewport" content="width=device-width, initial-scale=1"> <title></title> </head> <body> <input type="checkbox" name="" id="" class="check">全选/取消全选 <br> <input type="checkbox" name="num" id="" class="ball_checkbox">1<br> <input type="checkbox" name="num" id="" class="ball_checkbox">2<br> <input type="checkbox" name="num" id="" class="ball_checkbox">3<br> <input type="checkbox" name="num" id="" class="ball_checkbox">4<br> <script type="text/javascript"> let delete_checkbox = document.getElementsByClassName('check')[0]; let arr = true; delete_checkbox.addEventListener('click', function() { let num = document.getElementsByName('num'); for (let i = 0; i < num.length; i++) { num[i].checked = this.checked; } }) </script> </body> </html>
给下面所以复选框绑定点击事件，每次点击，都要循环查看下面所有的复选框是否有没选中的，上面全选就不选中；
