how to get the value of a text input in php class code example

Example: get text field value in php

<form method="post">
  <input type="text" name="deleteinput" class="button"/>
  <input type="submit" name="deletebtn" class="button" value="Delete single user data"/>
</form>
  // php 
<?php 
    $name = $_GET['deletebtn'];
    echo $name;
?>