jquery.maskedinput.js

First, include the jQuery and masked input javascript files.

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



<script 
src
=
"jquery.maskedinput.js"
 
type
=
"text/javascript"
></script>

Next, call the mask function for those items you wish to have masked.

jQuery
(
function
(
$
){


   $
(
"#date"
).
mask
(
"99/99/9999"
);


   $
(
"#phone"
).
mask
(
"[phone]"
);


   $
(
"#tin"
).
mask
(
"99-9999999"
);


   $
(
"#ssn"
).
mask
(
"999-99-9999"
);



});

Optionally, if you are not satisfied with the underscore ('_') character as a placeholder, you may pass an optional argument to the maskedinput method.

jQuery
(
function
(
$
){


   $
(
"#product"
).
mask
(
"99/99/9999"
,{
placeholder
:
" "
});



});

Optionally, if you would like to execute a function once the mask has been completed, you can specify that function as an optional argument to the maskedinput method.

jQuery
(
function
(
$
){


   $
(
"#product"
).
mask
(
"99/99/9999"
,{
completed
:
function
(){
alert
(
"You typed the following: "
+
this
.
val
());}});



});

You can now supply your own mask definitions.

jQuery
(
function
(
$
){


   $
.
mask
.
definitions
[
'~'
]=
'[+-]'
;


   $
(
"#eyescript"
).
mask
(
"~9.99 ~9.99 999"
);



});



http://digitalbush.com/projects/masked-input-plugin/