hello i'm new to jquery

so i write this code

```
link rel="stylesheet" href="http://<?=$_SERVER['HTTP_HOST']?>/css/jquery-ui.css" />
<script src="http://<?=$_SERVER['HTTP_HOST']?>/js/jquery-1.9.1.js"></script>
<script src="http://<?=$_SERVER['HTTP_HOST']?>/js/jquery-ui.js"></script>
$( "#d0" ).datepicker( "option", "dateFormat", "d M y" );

```

but it seems the images of the datepicker is missing

there should be arrow left and right to change the month at the top corners of the datepicker, but there is none, but i can still click the top corners to change the months

the close button on top right corner of the jquery dialog box also missing, but the button still works

what am i missing here?