title: error while calc A and B with jquery and php
body: <p>Iam getting error while add A to B with jquery and php </p>
  
  <pre><code>$('#add').dblclick(function(){
      var A = $('#A').val();
      var B = $('#B').val();
          $.ajax({
              type:'POST',
              datatype:'html',
              url:'ajax_doadd.php',
              cache:false,
              data:{xa:A,xb:B},
              success:function(data){                                 
                  if (isNaN(data)){
                   alert('Some going wrong .. '+ data.length);
                  }else{ alert('OK');
                                     }
  
          }
          });
      }
  }); 
  </code></pre>
  
  <p>ajax.doadd.php</p>
  
  <pre><code>$A =  $_POST['xa'];
  $B =  $_POST['xb'];
  
  $result = $A+$B;
  
  echo $result;
  </code></pre>
  
  <p>the result apprear not an numeric value </p>