You were right i found one place one jquery-1.8.3.min.js was externally included which may overriding richfaces default jquery library.
i removed that and it worked.
HI prashant sindhu,
if you are using external jquery's of higher versions. It may conflict the script of richfaces. and use of jquery object. so replace the jquery object with your own $ variable by using noConflict() method of jquery.
Ex: j$ = jQuery.noConflict();
Note: replace all $ variable in jquery plugins which you are using with j$ variable.