Test the Cookie length limit in different browsers

(1) No cookie of the same name is set on the current page;

(2) the cookie with the same name has been set on the current page;

The main test code is as follows:

  

   // A super-long string exceeding 4 K
   

   

    

     
      

       

Var longstring = 'dfsafdsafdfsafdsafdfsafdsafdsafdfsafdfsafdfs
       
Afdsafdfsafdsafdfsafdsafdfsafdfsafdsafdfs
       
Afdsafdfsafdsafdfsafdsafdfsafdfsafdsafdfsafdsaf
       
Dfsafdsafdfsafdsafdfsafdsafdfsafdfsafdsafdfsafdf
       
Safdsafdfsafdsafdfsafdsafdfsafdfsafdsafdfsafdsafdfsafdfsafdsafdfs
       
Afdsafdfsafdsafdfsafdsafdfsafdfsafdsafdfsafdsafdfsafdfsafdsafdsafdfsaf
       
Dsafdfsafdsafdfsafdsafdfsafdsafdsafdfsafdsafdfsafdfsafdsafdsafdfsafdsafd
       
Fsafdsafdfsafdsafdfsafdsafdfsafdfsafdsafdfsafdsafdfsafdfsafdsafdsafdfsa
       
Fdsafdfsafdsafdfsafdsafdfsafdsafdsafdfsafdsafdfsafdfsafdsafdsafdfsafdsafdf
       
Bytes
       
Bytes
       
Bytes
       
Bytes
       
Bytes
       
Dfsafdsafdfsafdsafdfsafdsafdfsafdfsafdsafdfsafdsafdfsafdfsaf
       
Dsafdfsa
       
Fdsafdfsafdsafdfsafdsafdfsafdsafdsafdfsafdsafdfsafdfsafdsafdsafdfsa
       
Fdsafdfsafdsafdfsafdsafdfsafdsafdsafdfsafdsafdfsafdfsafdsafdsafdfsafdsaf
       
Bytes
       
;


// Write cookie function
       

Function setcookie (name, value)
{
Var days = 1; // This cookie will be saved for 1 day
Var exp = new date ();
Exp. settime (exp. gettime () + days x 24x60*60*1000 );
Document. cookie = name + "=" + escape (value) + "; expires =" + exp. togmtstring ();
}

Function getcookie (name) // The cookie function.
{
Var arr = document. cookie. match (new regexp ("(^ |)" + name + "= ([^;] *) (; | $ )"));
If (arr! = Null) return unescape (arr [2]); return null;
}

// Set the cookie, which contains the two situations mentioned at the beginning of the article:
Setcookie ('test', 'Cookie already set ');

// Set the ultra-long cookie:
Setcookie ('test', longstring );

Alert (getcookie ('test '));
      
    
    

     

     

     
The test results are as follows:
    
    

     (1) No cookie of the same name is set on the current page;
    
  
    
 
     
 
      
 
       
 
        

         Browser version
        
 
 
       
 
        

         Output result
        
 
 
      
 
      
 
       
 
        

         Ie6
        
 
 
       
 
        

         Null
        
 
 
      
 
      
 
       
 
        

         Ie7
        
 
 
       
 
        

         Null
        
 
 
      
 
      
 
       
 
        

         Ie8
        
 
 
       
 
        

         Null
        
 
 
      
 
      
 
       
 
        

         Firefox
        
 
 
       
 
        

         Null
        
 
 
      
 
      
 
       
 
        

         Chrome
        
 
 
       
 
        

         Null
        
 
 
      
 
      
 
       
 
        

         Opera
        
 
 
       
 
        

         Null
        
 
 
      
 
     
    
    

     Conclusion:
    
    

     In the browsers of the above versions, writing strings larger than 4 KB (of course, different browsers may have different situations, some are 4095 bytes, some are 4096 bytes) will fail to be written,
    
    

     The write truncation cannot be performed.
    
    

     (2) the cookie with the same name has been set on the current page;
    
    
 
     
 
      
 
       
 
        

         Browser version
        
 
 
       
 
        

         Output result
        
 
 
      
 
      
 
       
 
        

         Ie6
        
 
 
       
 
        

         Null
        
 
 
      
 
      
 
       
 
        

         Ie7
        
 
 
       
 
        

         Null
        
 
 
      
 
      
 
       
 
        

         Ie8
        
 
 
       
 
        

         Cookie already set
        
 
 
      
 
      
 
       
 
        

         Firefox
        
 
 
       
 
        

         Cookie already set
        
 
 
      
 
      
 
       
 
        

         Chrome
        
 
 
       
 
        

         Cookie already set
        
 
 
      
 
      
 
       
 
        

         Opera
        
 
 
       
 
        

         Cookie already set
        
 
 
      
 
     
    
    

     Conclusion:
    
    

     When a value named 'test' already exists in browsers of the above versions, it is written to a string larger than 4 KB (of course, the situation may be different in different browsers, some are 4095 bytes, some are 4096 bytes:
    
    

     1. In ie6 and ie7, if a super-long string cannot be written, the cookie value with the original key 'test' will be affected. In the test results, the cookie value is cleared;
    
    

     2. In other browsers, the cookie value of the original same key name is not affected when the ultra-long string cannot be written. The original cookie value can still be read normally.