ASP.NET - How to check duplicate entries in Gridview textboxes?

Asked By aileni giri on 21-Mar-13 07:57 AM

i have one girdview   and  it having one textbox  coulmn  to enter  tax  amount,   while  entering  amount in textbox it   should  aloow duplicate entries......

for  this i  need   Javascript code  (or) c# code  ..

Please  help me out...