problem with required field validator for mandatory fields

Hi there,


In my webpage i m hving txtbox financial year , txtbox from year, txtbox endyear. Intially all three r mandatory fields. I want to do like this. when user enter value in financial year txtbox and submit then fromyear and endyear fields should not be mandatory. currently when submit it will check for all three. Is there any idea to implement it using codebehind or javascript.


Thanks
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