>I am trying to incorporate into my project a masked input plug-in (URL: http://digitalbush.com/projects/masked-input-plugin/)
>
>When I add this .js
>

><script src="Scripts/jquery-1.7.1.js" type="text/javascript"></script>
><script src="Scripts/jquery.maskedinput-1.2.2.min.js" type="text/javascript"></script>
>

>to a separate .aspx file in my project, the mask() function works very well.
>
>But when I add it to a page that uses Master page, I get error:
>

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

>
>The test code is identical in separate test page and the page that uses master page:
>
>

> <script type="text/javascript">
>        $(document).ready(function () {
>             $("#txtPhoneNumber").mask("(999) 9999-9999");
>        })
>    </script>
>

>
>The error (above) happens on the line .mask() above.
>
>How would you recommend to debug this situation? TIA

After beating my head against the wall for many hours, I give up on maskedinput.js. It works and then it does not work. And even when it works, it does not work well. For example, I wanted to use it in one textbox where user would be entering time; in hours and decimal. For example, 2.5 (for 2 and half hours). I set up the input mask to 999.99. What happens is that (when it works) if you enter any value of less than 5 digits (e.g. 2.5) the value disappears on leaving the textbox. The only way to make the number stay in the textbox is to enter all 5 digits (e.g. 888.33). I will have to relay on the user to enter the number in the correct format.
Just want to let those who helped me in this thread know.