How make a active WebPage

i have a text box in a WebPage and i want when the user type somthing in it , display it with no refresh

my php file that get data from user and display it:

    <?php 
$text = $_GET['text'];
echo $text;
 ?>

now the html file :

<form method="Get">
<input type="text" name="text">
    </form>

how can make it type $text when the user type in textBox.