Siva,

Great info. I also found the following on the w3c website:

2.9. The autocomplete attribute
The autocomplete attribute applies to the text, password, select, textarea,
date-related, time-related, numeric, email, and uri controls. The attribute
takes two values, on and off. The default, when the attribute is not
specified, is on.

The on value means the UA may store the value entered by the user so that if
the user returns to the page, the UA can prefill the form. The off value
means that the UA must not remember that field's value.

This specification does not define the autocompletion mechanism. UAs may
implement any system within the conformance criteria of this specification,
taking into account security and privacy concerns.

A UA may allow the user to disable support for this attribute. Support for
the attribute must be enabled by default, and the ability to disable support
should not be trivially accessible, as there are significant security
implications for the user if support for this attribute is disabled.

Banks frequently do not want UAs to prefill login information:

<p>Account: <input type="text" name="ac" autocomplete="off" /></p>
<p>PIN: <input type="text" name="pin" autocomplete="off" /></p>
In practice, this attribute is required by many banking institutions, who
insist that UAs with auto-complete features implement it before supporting
them on their Web sites. For this reason, it is implemented by most major
Web browsers already, and has been for many years.