Post Json data to PHP using jquer ajax

post-json-php.js

var data = {"data1": "val1", "data2": "val2", "data3": "val3"};
var dataEncoded = JSON.stringify(data);

$.ajax({
   type: "POST",
   url: "post-data.php",
   // The key needs to match your method's input parameter (case-sensitive).
   data:{"data":dataEncoded},
   dataType: "json",
   success: function(data){
       alert(data);
   },
   failure: function(errMsg) {
       alert(errMsg);
   }
});