What is a HTML Validator used for?

When you are writing HTML code, you want to ensure there are no errors/typos which may cause an error. To ensure there are no missing </> tags and typos, you can paste your HTML code into a free online HTML validator to ensure the code is correctly written before uploading your HTML page onto the Internet.

Using a HTML validator just ensures the HTML code is valid, it does not mean the webpage will display in the way you expected.

Its a good way to ensure the HTML code will run before you upload it onto the Internet and see if it displays correctly.