You just have to assign the Marathi font for the textbox e.g.:devnagri font, which will do it.
But you cannot expect all the users to have the same font. So, the best solution is to use Unicode fonts.
Check the below link. Using this tool you can get the Hindi text in Unicode.
http://www.google.com/transliterate/
If you are using the above unicode, then you can show the Marathi text in browsers......