A regular expression is created using pattern and flags:
Example:
Match all instances of "at" in a string globally.
var pattern1 = /at/g;
Match the first instance of "bat" or "cat", regardless of case.
var pattern2 = /[bc]at/i;
Match all three-character combinations ending with "at", regardless of case globally.
var pattern3 = /.at/gi;
The following metacharacters must be escaped when used as part of the pattern. The metacharacters are as follows:
( [ { \ ^ $ | ) ] } ? * + .
Here are some examples:
Match the first instance of "bat" or "cat", regardless of case.
var pattern1 = /[bc]at/i;
Match the first instance of "[bc]at", regardless of case.
var pattern2 = /\[bc\]at/i;
Match all three-character combinations ending with "at", regardless of case.
var pattern3 = /.at/gi;
Match all instances of ".at", regardless of case.
var pattern4 = /\.at/gi;
The preceding examples all define regular expressions using the literal form.