Date Validation Expressions

Follwing are different regular expressions used for date validation which you can use in any ASP.NET application to validate date using
RegularExpressionValidator

yyyy/mm/dd pattern
^/d{4}(/)[0-9][1-9](/)[0-3][0-9]$

mm/dd/yyyy format
\d{1,2}/\d{1,2}/\d{2,4}

//for mm/dd/yyyy
(0[1-9]1[012])[- /.](0[1-9][12][0-9]3[01])[- /.](1920)\d\d\

mm/dd/yyyy
((0[1-9][1-9])1[012])/((0[1-9][1-9])[12][0-9]3[01])/(1920)[0-9]{2}

Checks all validations
^((0?[13578]1012)(-\/)(([1-9])(0[1-9])([12])([0-9]?)(3[01]?))(-\/)((19)([2-9])(\d{1})(20)([01])(\d{1})([8901])(\d{1}))(0?[2469]11)(-\/)(([1-9])(0[1-9])([12])([0-9]?)(3[0]?))(-\/)((19)([2-9])(\d{1})(20)([01])(\d{1})([8901])(\d{1})))$