jquery实现全选和全不选功能

网上好多代码都是错的

 

 
  <! 
  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 
  >无标题文档 
  </ 
  title 
  > 
  
 
  </ 
  head 
  > 
  
 
  < 
  script  
  src 
  ="jquery-1.7.1.min.js" 
  ></ 
  script 
  > 
  
 
  < 
  script  
  type 
  ="text/javascript" 
  > 
  
    $(document).ready( 
  function 
   () {

        $( 
  " 
  #checkedAll 
  " 
  ).click( 
  function 
   () {

             
  // 
  alert("aa"); 
  
 
  

             
  if 
   ($( 
  this 
  ).attr( 
  " 
  checked 
  " 
  )) {  
  // 
   全选  
  
 
  
                $( 
  " 
  input[name='checkbox_name'] 
  " 
  ).each( 
  function 
   () {
                    $( 
  this 
  ).attr( 
  " 
  checked 
  " 
  ,  
  true 
  );
                });
            }
             
  else 
   {  
  // 
   取消全选  
  
 
  
                $( 
  " 
  input[name='checkbox_name'] 
  " 
  ).each( 
  function 
   () {
                    $( 
  this 
  ).attr( 
  " 
  checked 
  " 
  ,  
  false 
  );
                });
            }
        });

    }); 

 
  </ 
  script 
  >  
  
 
  
 
  < 
  body 
  > 
  
 
  < 
  input  
  type 
  ="checkbox" 
   name 
  ="checkbox_name" 
   id 
  ="checkbox_name_1" 
    
  />1 
  < 
  br  
  /> 
  
 
  < 
  input  
  type 
  ="checkbox" 
   name 
  ="checkbox_name" 
   id 
  ="checkbox_name_2" 
    
  />2 
  < 
  br  
  /> 
  
 
  < 
  input  
  type 
  ="checkbox" 
   name 
  ="checkbox_name" 
   id 
  ="checkbox_name_3" 
    
  />3 
  < 
  br  
  /> 
  
 
  < 
  input  
  type 
  ="checkbox" 
   name 
  ="checkbox_name" 
   id 
  ="checkbox_name_4" 
    
  />4 
  < 
  br  
  /> 
  
 
  < 
  input  
  type 
  ="checkbox" 
   name 
  ="checkedAll" 
   id 
  ="checkedAll" 
  />全选/取消全选 
  
 
  </ 
  body 
  > 
  
 
  </ 
  html 
  >