tabindex in timeselector control

Hi,
 
I have a timepicker control. upon selecting the time(am or pm) in
the control and giving a tab, focus is going to url rather than going to next
control in the form. I have given tabindex=10 to timepicker control and
tabindex=11 to next control(textbox).
 
I couldn't get a solution in google search.
I tried by onblur and onchange events in javascript but the events are not raising
when I select a text(am or pm) and give tab.
 
please help me in getting a solution.