SPServices: Using jQuery to auto fill current user information in SharePoint 2010

Using following script in your page by SharePoint Designer or Content Editor WP

<script language="javascript" src="/TimeSheet/jQuery%20Libraries/jquery-1.4.2.min.js" type="text/javascript"></script>

<script language="javascript" src="/TimeSheet/jQuery%20Libraries/jquery.SPServices-0.5.4.min.js" type="text/javascript"></script>

<script language="javascript" type="text/javascript">

$(document).ready(function() {

    var userDepartment = $().SPServices.SPGetCurrentUser({

        fieldName: "Department"

    });

    $("input[Title='Department']").val(userDepartment);    

});

</script>

In this script, we auto fill Department textbox by department of current user.

Reference