W3C HTML Validation

the the allows that - (https://validator.w3.org/#validate_by_input). this direct "check" the input" operation: into the by of service validation desired w3c. the checks to it button, activate validate using - documents the html that compliance is the made the the extension html the you markup current validity verify the pressing page service extension by of on of browser in way, w3c it to in of is and "validate the the provided page the the by current extracts service html copies of with html page possible - web w3c standards. markup