Jquery placeholder plugin error

Hello,

Please could you advise I am still getting error using jquery.placeholder.js.

error:
Unhandled exception at line 22, column 5 in http://localhost:52833/Scripts/ui.js

0x800a01b6 - Microsoft JScript runtime error: Object doesn't support property or method 'placeholder'Unhandled exception at line 22, column 5 in http://localhost:52833/Scripts/ui.js

0x800a01b6 - Microsoft JScript runtime error: Object doesn't support property or method 'placeholder'

This is input:

<input type="text" placeholder="Computer" name="searchComputer" data-autocomplete="@Url.Action("QuickNameSearch","SoftwareAudit")" />

Script is is refferenced in layout view in this order:
type="text/javascript" src="~/Scripts/jquery-1.6.2.js">script>

<script type="text/javascript" src="~/Scripts/jquery.unobtrusive-ajax.js">script>

<script type="text/javascript" src="~/Scripts/jquery-ui-1.8.11.js">script>

<script type="text/javascript" src="~/Scripts/jquery.placeholder.js">script>

<script type="text/javascript" src="~/Scripts/ui.js">script>

And plugin is called in this way: