Tryit Editor v1.8

Source Code:

<!DOCTYPE html>
<html>
<head>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js">
</script>
<script>
$(document).ready(function(){
  $("input").focus(function(){
    $("span").css("display","inline").fadeOut(2000);
  });
});
</script>
<style>
span
{
display:none;
}
</style>
</head>
<body>

<input>
<span>Can I have you phone number?</span>
<p>Click in the input field to get focus.</p>

</body>
</html>

Result:

W3Schools.com - Try it yourself

Edit the code above and click "Submit Code" to see the result.