Three letter country code validation
input type="text" name="country_code" pattern="[A-Za-z]{3}" title="Three letter country code"Email address validation
^[_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$Date validation[yyyy-mm-dd]
^(19|20)\d\d[- /.](0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])$| Regular Expression | Description |
|---|---|
| [abc] | Any character between the brackets |
| [^abc] | Any character not between the brackets |
| [0-9] | Any digit between the brackets |
| [^0-9] | Any digit not between the brackets |
| (x|y) | Any of the alternatives specified |
| [a-z] | Any character from lowercase a to z |
| [A-Z] | Any character from lowercase A to Z |
| [^a-zA-Z] | Any string not containing any of the characters ranging from a-z and A-Z. |
| ^.{2}$ | It matches any string containing exactly two characters. |
