Is it correct to use single quotes for HTML attributes?

Question

Recently I\'ve been seeing a lot of this:

Answer 1

If you want to the html to be valid html4 or xhtml then both single-quotes or double-quotes will work for attributes. HTML4 can be validated here: https://validator.w3.org/

If you are supporting only modern browsers (ie10 and higher) then you can use the html5 syntax which allows single quotes, double quotes, and no quotes (as long as there are no special characters in the attributes' value). HTML5 can be validated here: https://validator.w3.org/nu