jquery实现 全选

       $(function(){
                  
        $("#titleCheckbox").click(function () { 
            if( $("#titleCheckbox").attr("checked")==true){
                $("input[name='myCheckbox']").attr("checked", true);
            }else{
                $("input[name='myCheckbox']").attr("checked", false);
            }
       
        });    
     
      
     
       $("input[name='myCheckbox']").bind("click", function () {
            
           var  check_flag=true;
          $("input[name='myCheckbox']").each(function(){

               if($(this).attr("checked")==false){
                  $("#titleCheckbox").attr("checked", false);
                  check_flag=false;
                  return false; //跳出each循环
               }
                 
          } );
         
         
          if(check_flag){
          $("#titleCheckbox").attr("checked", true);
          }
         
         
       });
     
                 
                       
       });