Hi Vedha,
If you're not using Form Builder to create the form, and thus are not leveraging Form Runner, this is a tricky one, as this feature is implemented at the Form Runner level. You could of course re-implement this yourself, without using the code in Form Runner.
In essence, XForms adds the class xforms-visited to fields once the user "went through the field". So you would need to override the CSS not to show errors on the fields marked with the xforms-invalid class, unless they also have the xforms-visited class.
Then on save or submit, you'll want to show all errors, so mark all controls as visited, which you can do with with <xxf:setvisited>.
http://doc.orbeon.com/xforms/actions/extensions.htmlI hope this helps,
Alex
--
Follow Orbeon on Twitter: @orbeon
Follow me on Twitter: @avernet