Exporting HTML of a Webpage [on hold]

I am trying to build a web app that is a simple text editor. I then want the user to be able to click a button on the webpage and export the HTML of the contents of the text editor. This HTML should be posted elsewhere. I am unsure about how to accomplish the exporting HTML part.

Any ideas on where to begin/helpful tools to use? I don't really know where to begin.

Thank you!