Offline website builder with option to add html code in buttons

I want to create a simple website that will have only buttons. These buttons should have hmtl code (copy a message to clipboard on click). So, i'm looking for a free offline website builder that allows me to create buttons including html code when i click them. Instead of just move me to an another page, i want a builder that let me program the buttons so they can copy a message to clipboard or other html coding stuff