How to use the pattern attribute?
I have already turned over the internet, even in W3school, and I only see them informing the code "ready". With keys, interrogations, bars, cipher and various other parameters.
But I found nothing explaining how to use these parameters, what are they for?
1 answers
The pattern attribute in HTML 5 forms allows that form to be validated through a Regular Expression.
Regular expressions are a way of validating textual expressions that follow some kind of pattern and by applying this expression within the pattern parameter HTML will ensure that this pattern is satisfied.
Example:
You have a form that needs to receive the license plate of a car. This type of information in Brazil it follows a certain pattern: 3 Letters From A to Z, followed by a dash and finally 4 numbers from 0 to 9. You can express this in the following form:
<form action="#">
<label for="placa">Placa: </label>
<input type="text" name="website" pattern="[A-Za-z]{3}-[0-9]{4}">
<input type="submit">
</form>Before using the pattern attribute you need an understanding of how to work with regular expressions. Below are some articles that can help you help: