# Validators

# HTML5

HTML5 validator

Checks if the HTML code is standard compliant
- Checks if the HTML code is well structured
- Checks if tags are in the right place, are opened and closed correctly, ...
Check by
- address (URL)
- file upload
- text input
You can opt to Show the source, outline and/or image report of the HTML code

REMARK

Another W3C online HTML validator exists for older versions of HTML pages.
If you accidently upload an HTML5 document to this validator service, you are automatically redirected to the W3C online HTML5 validator

TIP

You can install the browser extension/add-on HTML Validator to validate HTML5 documents within (the console window of) your browser
- Available for Chrome (and Firefox)
How to use?
- Open an HTML-file in Chrome
- Open the Developer tools (F12) and go to the tab HTML validator
- Click on the blue button W3C Online to see the W3C validation results
  (by default or if you click on the Offline button, a different algorithm than the one used by W3C is applied to check your HTML-code)

CSS validator

Checks if the CSS code is standard compliant
3 tabs
- Validate By URI
- Validate By file upload
- Validate By direct input
More Options
- Profile: CSS Level 3 + SVG is the default (and recommended) value
- Warnings: besides the default Normal report, you can opt to see All, only the Most important or No warnings
- For Medium and Vendor Extensions, you kan keep the default values (for now)