javascript terminal in browser
<ctrl><shft>J

about:config > turn on devtools.chrome.enabled

https://javascript.info

https://developer.mozilla.org/en-US/docs/Web/API/FileReader/readAsDataURL

http://www.htmlfivewow.com/demos/terminal/terminal.html

https://www.noupe.com/design/html5-filesystem-api-create-files-store-locally-using-javascript-webkit.html