Regular Expressions aka Regex are expressions that define a search pattern. They are widely used for validation purposes, like email validation, url validation, phone number validation and so on. Forming Regex: A regex is written between two forward slashes (/) delimiters. These delimiters are essential only for certain Regex engines (JS,PHP..). It is then followed by 2 flags: i : Ignore case Flag, ignores the case(uppercase/lowercase) of the input string …read more