Question

I want to validate a value from html form in JavaScript function, the format is a bit flexible.

i.e,

1 or 2 or 3 or 4 or 5 integer value followed by back slash(/) followed by 1 or 2 or 3 integers.

Example.

12345/123 is a valid value.

1234/12 is a valid value.

123/123 is a valid value.

1/1 is a valid value.

a/123 is NOT a valid value.

123/% in NOT a valid value.

Answer 1

You can try this regex: ^\d{1,5}\/\d{1,3}$

Example:

var re = /^\d{1,5}\/\d{1,3}$/;

console.log(re.test('12345/123')); // true
console.log(re.test('1234/12')); // true
console.log(re.test('123/1')); // true
console.log(re.test('12/123')); // true
console.log(re.test('1/123')); // true
console.log(re.test('a/123')); // false
console.log(re.test('123456/123'); // false

That said, you should start from the basics:

http://en.wikipedia.org/wiki/Regular_expression

http://www.regular-expressions.info/

https://developer.mozilla.org/en-US/docs/JavaScript/Guide/Regular_Expressions

https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/RegExp

Here you can find many examples: http://regexlib.com/?AspxAutoDetectCookieSupport=1