Regular expression for validating special characters dating com new
The validation succeeds only if the user input matches the pattern.
For example, the pattern matches the 'el' in "angel" and the 'le' in "angle" and also the 'l' in "oslo".
For example, use two backslash characters (\) to represent a backslash character.
The following rules govern regular expressions that match a single character: th parenthesized subexpression.
If the regular expression remains constant, using this can improve performance.
Or calling the constructor function of the Using the constructor function provides runtime compilation of the regular expression.