Html Form Input Validation
Form Input Validation general summary:
It is the way in which we can validate all the data entered in our html forms, to be able to send only correct data to the server. It is called client side validation, because it is carried out on the user's computer, that is, in the user's browser through the web page.
There are 2 ways to do it: Using built-in form validation or using JavaScript.
Built-in form validation: validate most user data without relying on JavaScript. This is done by using validation attributes on form elements.
Validation with JavaScript with The Constraint Validation API: Consists of a set of methods and properties that we can use to more easily implement our JavaScript code. We can also validate the form input data only using JavaScript without an API; sometimes we will not be able to use the validation API, since some functionality is not compatible with all browsers. Or sometimes what we have to verify is something so particular that we will not find it in a built-in API.
Built-in form validation: Easier to implement, but it is not compatible with all browsers, and it is not customizable.
Validation with JavaScript: It is more difficult since we have to create the code ourselves to validate the data, but we can completely customize it.