CODEWITHSUNDEEP
javascriptregex
gothamprince
gothamprince

Reputation: 37

Regular Expression in JavaScript - Not Filtering Properly

I have a regular expression that I am attempting to use to control user input to only allow letters A-D(case insensitive) followed by a numerical value between 1-16.

Ex// A12, C5 are valid entries, but B18 would be invalid as would H2.

The regular expression I am using flags incorrect input based on the alphabetical value, but not the numerical - so in my previous example it is correctly flagging H2, but is allowing B18 to be entered.

I am fairly new to regex and so I am unsure where I've gone astray. Any help would be greatly appreciated!

My current expression is as follows:

var regex = new RegExp(/([A-Da-d]{1}[1-9]{1}|[A-Da-d]{1}[1]{1}[0-6]{1})/);

Thanks again!

Upvotes: 1

Views: 31

Answers (2)

Federico Piazza
Federico Piazza

Reputation: 30995

You could use a regex like this with insensitive flag:

^[a-d](?:1[0-6]|[0-9])$

Working demo

Upvotes: 0

Robby Cornelissen
Robby Cornelissen

Reputation: 97140

This expression will do it:

/^[A-D]([1-9]|1[0-6])$/i


var re = /^[A-D]([1-9]|1[0-6])$/i;

console.log(re.test('A12'));
console.log(re.test('C5'));
console.log(re.test('H12'));
console.log(re.test('B18'));

Upvotes: 1

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