Hello Siva,
if I have understood correctly, you trying are trying to generate an email in html format on client side, using mailto. So I did a little research and I think, what you are trying to accomplish is simply not possible, see: http://www.ietf.org/rfc/rfc2368.txt.
"The special hname "body" indicates that the associated hvalue is the body of the message. The "body" hname should contain the content for the first text/plain body part of the message. The mailto URL is primarily intended for generation of short text messages that are actually the content of automatic processing (such as "subscribe" messages for mailing lists), not general MIME bodies."
Maybe you are lucky and some, email clients will detect your html code and convert the email, but this depends on the implementation of your mail client.
Kind regards Martin
