Different browsers handle errors in HTML in different ways. In other words, if there are errors in your code, it is quite unclear how the Web page will appear in different browsers. And only if there are no errors in the code, most browsers will show the page in the same way. If you start to design with CSS, but the HTML does not meet certain requirements, the differences can become even more significant.
So, if we make sure that our HTML code complies with the standards, there will be much less problems in the future that are related to incorrect display of pages in different browsers.
What is validation?
Validation is the verification of the document by a special program - the validator for compliance with the established web standards and the detection of existing errors. These standards are called a specification (developed by the World Wide Web Consortium, or abbreviated W3C).
The work of the validator is as follows: first, the document type is defined (specified using
<!DOCTYPE>), and then the HTML code is checked for correctness and absence of errors. It also verifies the correct use of the name tags and their nesting.
How do I use the validator?
The official validator interface provides three ways to test your HTML.
If the page is online, you can simply print or copy the desired URL to the form, click the
Check button, and the service program will find your code and check it.
Check the file to download
You can click the
Browse button and select the file on your computer. After that, click the
Check button, and the browser will download the file from your computer to the remote server, and the service program checks it.
Checking inserted code
Copy your code and paste it into the form. Then click the
Check button and the service program will check your HTML.