Ajax cannot accept the returned information

Ajaxcannot receive the returned information a.html: & lt ;! DOCTYPE & nbsp; html & nbsp; PUBLIC & nbsp; "-// W3C // DTD & nbsp; XHTML & nbsp; 1.0 & nbsp; Transitional // EN" & nbsp; "http: // ww ajax cannot receive the returned information
A.html:

 
  

  

  
   

   Untitled Document
   

   
    
Script
    

    
     
Script
     

     
      
Function check ()
      
{
      
Var con = document. getElementById ('con '). value;
      
// Alert (con );
      

      
// Create ajax
      
Var ajax = createAjax ();
      
// Whether the creation is successful
      
// Alert (ajax );
      
Var data = new Date ();
      

      
Var urlStr = 'B. php? Action = '+ data. getTime ();
      
// Alert (urlStr );
      
$. Ajax ({
      
Url: urlStr,
      
Datatype: "json ",
      
Cache: false,
      
Success: function (response ){
      
Alert (response );
      
}
      
});
      
}
      
Script
      

      

      

      

      

      

      

     
    
   
  
 

B. php:

echo true;

Ajax cannot accept the information returned by B. php. where is the error? thank you.
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Won't you jump after you click the button?
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