Use this as a bookmarklet in your browser: http://staticresource.com/on-screen-console.mp4

on-screen-bookmarklet.js

javascript:const wrapper = document.createElement('aside'); const style = document.createElement('style'); const toggle = document.createElement('button'); const input = document.createElement('textarea'); const button = document.createElement('button'); const output = document.createElement('pre'); wrapper.id = 'jswrapper'; wrapper.className = 'open'; toggle.id = 'jstoggle'; button.textContent = 'Evaluate'; style.textContent = ` #jswrapper, #jswrapper * { box-sizing: border-box; } #jswrapper { position: fixed; bottom: 0; right: 0; width: 100%; transform: translateY(0); transition: transform .2s; } #jswrapper.open { transform: translateY(100%); } #jswrapper #jstoggle { position: absolute; right: 0; top: -2em; height: 2em; width: 2em; } #jstoggle::before { content: '⬇'; } .open #jstoggle::before { content: '⬆'; } #jswrapper textarea, #jswrapper button, #jswrapper pre { display: block; width: 100%; margin: 0; padding: .5em; font-size: 14pt; } #jswrapper pre, #jswrapper textarea { background: white; height: 5em; overflow-y: auto; } `; wrapper.appendChild(style); wrapper.appendChild(toggle); wrapper.appendChild(input); wrapper.appendChild(button); wrapper.appendChild(output); document.body.appendChild(wrapper); function runCode() { const js = input.value; input.value = ''; return eval(js); } button.addEventListener('click', runCode); toggle.addEventListener('click', event => { event.target.parentElement.classList.toggle('open'); }); window.console = { original: console, ...console, output: (strings, func) => strings.forEach(string => { output.textContent += `${func}: ${string}\n`; output.scrollTop = output.scrollHeight; return console.original[func](string); }), log: (...strings) => console.output(strings, 'log'), info: (...strings) => console.output(strings, 'info'), warn: (...strings) => console.output(strings, 'warn'), error: (...strings) => console.output(strings, 'error') };

on-screen-console.js

const wrapper = document.createElement('aside');
const style = document.createElement('style');
const toggle = document.createElement('button');
const input = document.createElement('textarea');
const button = document.createElement('button');
const output = document.createElement('pre');

wrapper.id = 'jswrapper';
wrapper.className = 'open';
toggle.id = 'jstoggle';
button.textContent = 'Evaluate';
style.textContent = `
  #jswrapper,
  #jswrapper * {
    box-sizing: border-box;
  }
  #jswrapper {
    position: fixed;
    bottom: 0;
    right: 0;
    width: 100%;
    transform: translateY(0);
    transition: transform .2s;
  }
  #jswrapper.open {
    transform: translateY(100%);
  }
  #jswrapper #jstoggle {
    position: absolute;
    right: 0;
    top: -2em;
    height: 2em;
    width: 2em;
  }
  #jstoggle::before {
    content: '⬇';
  }
  .open #jstoggle::before {
    content: '⬆';
  }
  #jswrapper textarea,
  #jswrapper button,
  #jswrapper pre {
    display: block;
    width: 100%;
    margin: 0;
    padding: .5em;
    font-size: 14pt;
  }
  #jswrapper pre,
  #jswrapper textarea {
    background: white;
    height: 5em;
    overflow-y: auto;
  }
`;

wrapper.appendChild(style);
wrapper.appendChild(toggle);
wrapper.appendChild(input);
wrapper.appendChild(button);
wrapper.appendChild(output);
document.body.appendChild(wrapper);

function runCode() {
  const js = input.value;
  input.value = '';
  return eval(js);
}

button.addEventListener('click', runCode);

toggle.addEventListener('click', event => {
  event.target.parentElement.classList.toggle('open');
});

window.console = {
  original: console,
  ...console,
  output: (strings, func) => strings.forEach(string => {
    output.textContent += `${func}: ${string}\n`;
    output.scrollTop = output.scrollHeight;
    return console.original[func](string);
  }),
  log: (...strings) => console.output(strings, 'log'),
  info: (...strings) => console.output(strings, 'info'),
  warn: (...strings) => console.output(strings, 'warn'),
  error: (...strings) => console.output(strings, 'error')
};