js checkbox

 1 //复选框全选
 2 var oCheckBox ={
 3     _check_all: function(obj){
 4         if("all" == obj.name){
 5             if(obj.checked){
 6                 $("#days input:checkbox").each(function(){
 7                     this.checked = true;
 8                 });
 9             }else{
10                  $("#days input:checkbox").each(function(){
11                     this.checked = false;
12                 });
13             }
14         }else{
15             var oAll = document.getElementById("checkall");
16             if(obj.checked){
17                 var allDays = document.getElementById("days").childNodes;
18                 for (var i=0; i < allDays.length; i++)
19                 {
20                     if((allDays[i].type == "checkbox") &&  !allDays[i].checked){
21                          oAll.checked = false;
22                          return;
23                     }
24                 }
25                 oAll.checked = true;
26             }else{
27                 oAll.checked = false;
28             }
29         }
30     },
31     _init_checkbox:function(){
32         $("#days input:checkbox").each(function(){
33             $(this).attr("checked", false);
34         });
35         $("#checkall").attr("checked", false);
36     }
37 }