Stage 1
Symbol Explanation
^ Start of string
$ End of string
. Any single character
+ One or more character
\ Escape Special characters
? Zero or more characters
Input exactly match with “abc”
var A = /^abc$/;
Input start with “abc”
var B = /^abc/;
Input end with “abc”
var C = /abc$/;
Input “abc” and one character allowed Eg. abcx
var D = /^abc.$/;
Input “abc” and more than one character allowed Eg. abcxy
var E = /^abc.+$/;
Input exactly match with “abc.def”, cause (.) escaped
var F = /^abc\.def$/;
Passes any characters followed or not by “abc” Eg. abcxyz12....
var G = /^abc.+?$/
Stage 2
Char Group Explanation
[abc] Should match any single of character
[^abc] Should not match any single character
[a-zA-Z0-9] Characters range lowercase a-z, uppercase A-Z and numbers
[a-z-._] Match against character range lowercase a-z and ._- special chats
(.*?) Capture everything enclosed with brackets
(com|info) Input should be “com” or “info”
{2} Exactly two characters
{2,3} Minimum 2 characters and Maximum 3 characters
{2,} More than 2 characters
Put together all in one URL validation.
var URL = /^(http|https|ftp):\/\/(www+\.)?[a-zA-Z0-9]+\.([a-zA-Z]{2,4})\/?/;
URL.test(“http://9lessons.info”); // pass
URL.test(“http://www.9lessons.info”); // pass
URL.test(“https://9lessons.info/”); // pass
URL.test(“http://9lessons.info/index.html”); // pass
Stage 3
Short Form Equivalent Explanation
\d [0-9] Any numbers
\D [^0-9] Any non-digits
\w [a-zA-Z0-9_] Characters,numbers and underscore
\W [^a-zA-Z0-9_] Except any characters, numbers and underscore
\s - White space character
\S - Non white space character
var number = /^(\+\d{2,4})?\s?(\d{10})$/; // validating phone number
number.test(1111111111); //pass
number.test(+111111111111); //pass
number.test(+11 1111111111); //pass
number.test(11111111); //Fail
