<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <button onclick="selectAll()">全选</button> <button onclick="Cancel()">取消</button> <button onclick="reverse()">反选</button> <table border="1px"> <tr> <td><input type="checkbox"></td> <td>123</td> <td>123</td> <td>123</td> </tr> <tr> <td><input type="checkbox"></td> <td>456</td> <td>456</td> <td>456</td> </tr> <tr> <td><input type="checkbox"></td> <td>789</td> <td>789</td> <td>789</td> </tr> <tr> <td><input type="checkbox"></td> <td>abc</td> <td>abc</td> <td>abc</td> </tr> </table> <script> function selectAll() { var inputs=document.getElementsByTagName('input'); for (var i=0; i<inputs.length; i++) { var input=inputs[i]; input.checked=true; }; }; function Cancel() { var inputs=document.getElementsByTagName('input'); for (var i=0; i<inputs.length; i++) { var input=inputs[i]; input.checked=false; }; }; function reverse() { var inputs=document.getElementsByTagName('input'); for (var i=0; i<inputs.length; i++) { var input=inputs[i]; // if (input.checked) { // input.checked=false; // }else { // input.checked=true; // }; input.checked=!input.checked; // 两种都可以，这种更简洁 }; }; </script> </body> </html>
练习：全选取消反选
while True:
print('studying...')