仅在PHP中单击按钮时显示密码

How to display a Button, when it is clicked, It display a PHP code which then displays content from Database, specifically I have created an SQL query in PHP where I am displaying user's details from my table, like Email, Username, Password. I want to make Password hidden, so when user click on "display" button, only then the password will be shown. Below is my php code to display all data from database:

{
<?php
include_once('confi.php');
//*********retrieving data from Database**********
$result = mysql_query("SELECT id,name, email, username, password  FROM demo");
while ($row = mysql_fetch_array($result, MYSQL_BOTH)) {
printf ("</br> ID: %s </br> Name: %s  </br> Email: %s </br> Username: %s </br> Password: %s </br>",  $row[0], $row[1], $row[2], $row[3], $row[4]);
} 
?>
}

I want to make password visible only when a button or anything like "show password" button is clicked. How can I make that?

Thanks in advance.

set the input field type is password and show the password when user click the checkbox . change the field type to text using jquery

$(document).ready(function(){

  $(':checkbox').change(function(){
  
    if($(this).is(':checked'))
      {
        
        $(this).prev('input').attr('type','text');
        
        }
    else
      {
          $(this).prev('input').attr('type','password');
        }
    
  
  });

});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="password" id="test1" value="a" />
<input id="test2" type="checkbox" />Show password

</div>
Using jquery we can do this . Here's a link (http://jsfiddle.net/herdiansc/dnznh/8/)