Can anyone give me some source where i can learn about " pattern in input tag"?

Answer 1

Yes.
You can see this article and learn something: https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/pattern

Answer 2

Ok, you can use pattern attribute to validate the input using regular expression.
eg: here in this code, I've given regular expression pattern that accepts only number of 5 digits.
Play with it and you can learn something.
https://code.sololearn.com/W7f840lU4vn9/?ref=app

Answer 3

March Zucherberg 😣 mdn/w3schools 🚫