Response.AppendHeader( "Cache-Control" , "no-cache" );
Response.AppendHeader( "Cache-Control" , "private" );
Response.AppendHeader( "Cache-Control" , "no-store" );
Response.AppendHeader( "Cache-Control" , "must-revalidate" Response.AppendHeader( "Cache-Control" , "max-stale=0" );
Response.AppendHeader( "Cache-Control" , "post-check=0" );
Response.AppendHeader( "Cache-Control" , "pre-check=0" ); Response.AppendHeader( "Pragma" , "no-cache" );
Add the above code in Page_load event of the page and remove <outputcache> tag at page level.the page will be reloaded on click of back button in opera emulator.(as we removed the cache.