关于反选和统计选中个数的问题解决我还不太懂，有待进一步学习和理解：
| <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> | |
| <html xmlns="http://www.w3.org/1999/xhtml"> | |
| <head> | |
| <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> | |
| <title>复选框（checkbox）全选/全不选/返选</title> | |
| <style> | |
| body,dl,dt,dd,p{margin:0;padding:0;} | |
| body{font-family:Tahoma;font-size:12px;} | |
| label,input,a{vertical-align:middle;} | |
| label{padding:0 10px 0 5px;} | |
| a{color:#09f;text-decoration:none;} | |
| a:hover{color:red;} | |
| dl{120px;margin:10px auto;padding:10px 5px;border:1px solid #666;border-radius:5px;background:#fafafa;} | |
| dt{padding-bottom:10px;border-bottom:1px solid #666;} | |
| dt label{font-weight:700;} | |
| p{margin-top:10px;} | |
| </style> | |
| <script type="text/javascript"> | |
| window.onload = function () | |
| { | |
| var oA = document.getElementsByTagName("a")[0]; | |
| var oInput = document.getElementsByTagName("input"); | |
| var oLabel = document.getElementsByTagName("label")[0]; | |
| var isCheckAll = function () | |
| { | |
| for (var i = 1, n = 0; i < oInput.length; i++) | |
| { | |
| oInput[i].checked && n++ | |
| } | |
| oInput[0].checked = n == oInput.length - 1; | |
| oLabel.innerHTML = oInput[0].checked ? "全不选" : "全选" | |
| }; | |
| //全选/全不选 | |
| oInput[0].onclick = function () | |
| { | |
| for (var i = 1; i < oInput.length; i++) | |
| { | |
| oInput[i].checked = this.checked | |
| } | |
| isCheckAll() | |
| }; | |
| //反选 | |
| oA.onclick = function () | |
| { | |
| for (var i = 1; i < oInput.length; i++) | |
| { | |
| oInput[i].checked = !oInput[i].checked | |
| } | |
| isCheckAll() | |
| }; | |
| //根据复选个数更新全选框状态 | |
| for (var i = 1; i < oInput.length; i++) | |
| { | |
| oInput[i].onclick = function () | |
| { | |
| isCheckAll() | |
| } | |
| } | |
| } | |
| </script> | |
| </head> | |
| <body> | |
| <dl> | |
| <dt><input type="checkbox" id="checkAll" /><label>全选</label><a href="javascript:;">反选</a></dt> | |
| <dd> | |
| <p><input type="checkbox" name="item" /><label>选项（一）</label></p> | |
| <p><input type="checkbox" name="item" /><label>选项（二）</label></p> | |
| <p><input type="checkbox" name="item" /><label>选项（三）</label></p> | |
| <p><input type="checkbox" name="item" /><label>选项（四）</label></p> | |
| <p><input type="checkbox" name="item" /><label>选项（五）</label></p> | |
| <p><input type="checkbox" name="item" /><label>选项（六）</label></p> | |
| <p><input type="checkbox" name="item" /><label>选项（七）</label></p> | |
| <p><input type="checkbox" name="item" /><label>选项（八）</label></p> | |
| <p><input type="checkbox" name="item" /><label>选项（九）</label></p> | |
| <p><input type="checkbox" name="item" /><label>选项（十）</label></p> | |
| </dd> | |
| </dl> | |
| <center>1、切换全选/全不选文字；2、根据选中个数更新全选框状态；</center> | |
| </body> | |
| </html> | |