Placeholder for datetime input field

Form loads with a text input and placeholder, on focus it changes the input type to datetime-local

HTML

<form action="" method="post">
    <div class="datetime">
        <input type="text" id="datetime1" placeholder="Enter the starting date"  >
    </div>
</form>

JavaScript

$(document).ready(function(){
    $("#datetime1").focus( function() {
	    $(this).attr({type: 'datetime-local'});
      });
});