Javascript validation to allow only string followed by number

Question

I want to restrict the user to enter in textbox only string followed by number only for e.g

AA1->true
AA1A->False
AA12->True
AB12AA14AB->false
12AA->false
ABC12->false
AA->false

So please let me know how can I add validation for above condition/cases using javascript.

Do you want to know how to validate this, or do you want to get an idea how js code can know if the input is valid? — Chayim Friedman
– Chayim Friedman, Commented Aug 17, 2018 at 6:51
learn about regex in jquery or javascrit.. it will help you more — Avi
– Avi, Commented Aug 17, 2018 at 6:52
validate by regex is what you need. try [A-Z]+[0-9]+ for example — dorintufar
– dorintufar, Commented Aug 17, 2018 at 6:52
ABC12 is a alphabetical characters followed by numeric characters, shouldn't it be true as well? — CertainPerformance
– CertainPerformance, Commented Aug 17, 2018 at 6:53

CertainPerformance · Accepted Answer · 2018-08-17 06:52:21Z

2

Use a regular expression:

const validate = str => /^[A-Z]+\d+$/.test(str);
`AA1
AA1A
AA12
AB12AA14AB
12AA
ABC12
AA`
  .split('\n')
  .forEach(str => console.log(validate(str)));

^ indicates the start of the string, [A-Z]+ matches one or more uppercase alphabetical characters, \d+ matches one or more numbers, and $ matches the end of the string.

answered Aug 17, 2018 at 6:52

CertainPerformance

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Comments

Sunil Aware · Accepted Answer · 2018-08-17 07:00:02Z

1

function isStrEndWithNum(str){ if(str) return !isNaN(str[str.length-1]); return false; }

answered Aug 17, 2018 at 7:00

Sunil Aware

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Comments

Rabbid76 · Accepted Answer · 2018-08-17 07:04:53Z

0

You can use the .test function which is present in JavaScript

/^([\w]+[0-9])$/.test('YourStringHere');

i am just confused with second last condition of yours.

Other than that all your conditions are passed with the above code.

edited Aug 17, 2018 at 7:04

Rabbid76

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answered Aug 17, 2018 at 6:59

unmeshrulz

1

3 Comments

Pankaj Over a year ago

my second last condition is don’t allow consecutive alphabets followed by number like ABC12

Pankaj Over a year ago

Using above code if I enter in textbox like 'aa1212dd12' it allows.In my case it don't allow.Only aa12,BB45 allow.

unmeshrulz Over a year ago

Sorry for the Late reply but i think this will resolve the issue /^([A-Z]{1})(\d{1})|([A-Z]{1})(\d{2})|([A-Z]{2})(\d{1})|([A-Z]{2})(\d{2})|([A-Z]{3})(\d{1})$/.test("Your String Here")

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