I see. Thanks for the reply.

I was trying to do validation using html5. The 'required' feature worked fine in Opera 20, but the validation bubble message didn't show up like what it was supposed to be shown in IE 10 & Firefox 28. I tried to search for the solution over the internet but no avail. People told me the problem should not be appeared in Opera version 16 above. I thought a pink bubble validation message was supposed to be appeared. I just want to know whether Opera 20 didn't support this validation bubble message any longer or is it just a bug that only I experience alone? Can anyone tell me what is going wrong actually? Thanks.

Browser: Opera 20
OS: Window 7