How can I validate user input in JavaScript?

How can I validate user input in JavaScript?

You can use regular expressions, built-in methods, or libraries like Joi for input validation. What type of input are you validating?

I need to validate an email address.

You can use a regular expression like this: /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/ to check if the email format is correct.

What if the input is empty?

You can check if the input is empty by using an if statement: if (inputValue.trim() === '') { /* handle empty input */ }.

Are there any libraries that can help with this?

Yes, libraries like Joi and Validator.js can simplify input validation significantly.