AJAX不使用Jquery从PHP文件中获取数据

I'm trying post data to PHP file but i can't receive any data from PHP file. Let me add codes. This is my jQuery function:

$(document).ready(function () {

$(function () {
$('a[class="some-class"]').click(function(){

   var somedata = $(this).attr("id");

   $.ajax({
      url: "foo.php", 
      type: "POST",
      data: "id=" + somedata,

      success: function(){
          $("#someid").html();
      },
      error:function(){
          alert("AJAX request was a failure");
      }
    });
    });
    });
});

This is my PHP file:

<?php
$data = $_POST['id'];

$con = mysqli_connect('localhost','root','','somedatabase');
if (!$con) {
  die('Could not connect: ' . mysqli_error($con));
}

mysqli_select_db($con,"database");
$sql="SELECT * FROM sometable WHERE id = '".$data."'";
$result = mysqli_query($con,$sql);


while($row = mysqli_fetch_array($result)) {

 echo $row['info'];

 }

mysqli_close($con);

?>

This what i have in HTML file:

<p id="someid"></p>

<a href="#page2" class="some-class" id="1">Data1</a>
<a href="#page2" class="some-class" id="2">Data2</a>

Note: This website is horizontal scrolling and shouldn't be refreshed. When i'm clicking links (like Data1) it's going to another page without getting data from PHP file

You have a few problems:

1. You are not using the data as mentioned in the other answers:
   success: function(data){ $("#someid").html(data); },
2. You are not cancelling the default click action so your link will be followed:
   $('a[class="some-class"]').click(function(e){ e.preventDefault(); ...;
3. As the id's are integers, you can use data: "id=" + somedata, although sending an object is safer in case somedata contains characters that need to be escaped:
   data: {"id": somedata},;
4. You have an sql injection problem. You should cast the variable to an integer or use a prepared statement:
   $data = (int) $_POST['id'];;
5. As also mentioned in another answer, you have two $(document).ready() functions, one wrapping the other. You only need one.

success: function(){
          $("#someid").html();
      },

should be:

success: function(data){
          $("#someid").html(data);
      },

You should add parameter in success

success: function(data){ //Added data parameter
      console.log(data);
      $("#someid").html(data);
  },

The data get the values what you echo in PHP end.

This:

  success: function(data){
      $("#someid").html(data);
  },

and you have two document ready, so get rid of:

$(document).ready(function () { ...

});

data: "id=" + somedata,

Change it to:

data: { id : somedata }