Regular expressions are constructed in the same way that arithmetic expressions are created. That is, small expressions are combined using a variety of metacharacters and operators to create larger expressions.
Constructing a Regular Expression
You construct a regular expression by putting the various components of the expression pattern between a pair of delimiters. For JScript, the delimiters are a pair of forward slash (/) characters. For example:
For VBScript, a pair of quotation marks ("") delimit regular expressions. For example:
In both of the examples shown above, the regular expression pattern (expression) is stored in the Pattern property of the RegExp object.
The components of a regular expression can be individual characters, sets of characters, ranges of characters, choices between characters, or any combination of all of these components.