Auto type in noVNC (Proxmox)

ProxmoxAutoType.js

(async () => {
  const text = prompt("Enter text to type:");
  const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));
  const input = document.getElementById("noVNC_keyboardinput");
  const keydown = (key) => input.dispatchEvent(new KeyboardEvent("keydown", { key }));
  for (let i = 0; i < text.length; i++) { keydown(text[i]); await sleep(50); }
})();

By integrating the functionality from https://github.com/aggregate1166877/noVNC-Paste-Tool/blob/primary/paste-tool.js, now we can paste text through a nice GUI.😎

(function() {
  var input = '';
  var delay = '100';
  var index = -1;

  var mainDivId = '00novnccustompastetool0947-maindiv';
  var textId = '00novnccustompastetool0947-textinput';
  var numId = '00novnccustompastetool0947-numinput';


  function updateUserInput(event) {
    event.preventDefault();
  }

  function paste(event) {
    event.preventDefault();
    var userInput = document.getElementById(textId);
    input = userInput.value;

    var userNumInput = document.getElementById(numId);
    delay = Number(userNumInput.value);
    if (!delay) {
      alert('Cannot proceed: delay number is invalid.');
      return close();
    }

    close(event);
    setTimeout(tick, 500);
  }

  function close(event) {
    event.preventDefault();
    var mainDiv = document.getElementById(mainDivId);
    document.body.removeChild(mainDiv);
  }

  function showGui() {
    var div = document.createElement('div');
    div.id = mainDivId;
    div.style.position = 'fixed';
    div.style.zIndex = '9999999999';
    div.style.backgroundColor = 'rgb(221 221 221 / 90%)';
    div.style.top = '0';
    div.style.left = '0';
    div.style.right = '0';
    div.style.padding = '8px';
    div.style.height = '168px';

    div.innerHTML = '<b>Paste your text</b><br>' +
      'Note: Use your mouse for copying and pasting because the KVM console ' +
      'snatches all input and this is the only sane work-around.' +
      '<br>';

    var textInput = document.createElement('textarea');
    textInput.id = textId;
    textInput.onkeydown = updateUserInput;
    textInput.style.display = 'block';
    textInput.style.width = '100%';
    textInput.style.marginBottom = '8px';

    var inputDesc = document.createElement('label');
    inputDesc.innerHTML = 'Per-key delay in ms:&nbsp;';
    inputDesc.title = 'Sending keys too fast can cause issues (such as ' +
      'skipped keys); the delay helps alleviate this.';

    var numInput = document.createElement('input');
    numInput.title = inputDesc.title;
    numInput.setAttribute('type', 'number');
    numInput.setAttribute('min', '1');
    numInput.setAttribute('max', '100000');
    numInput.value = delay;
    numInput.id = numId;

    var ok = document.createElement('button');
    ok.innerText = 'Paste';
    ok.onclick = paste;
    ok.style.margin = '8px';

    var cancel = document.createElement('button');
    cancel.innerText = 'Cancel';
    cancel.onclick = close;

    div.append(textInput);
    div.append(inputDesc);
    div.append(numInput);
    div.append(document.createElement('br'));
    div.append(cancel);
    div.append(ok);

    document.body.append(div);
  }

  const noVNCinput = document.querySelector('iframe').contentDocument.getElementById("noVNC_keyboardinput");
  const keydown = (key) => noVNCinput.dispatchEvent(new KeyboardEvent("keydown", { key }));

  function encodeAndSendKey(character) {
    if (character === '\r') {
      return;
    }
    if (character === '\t') {
      keydown("Tab");
      return;
    }
    if (character === '\n') {
      keydown("Enter");
      return;
    }
    keydown(character);
  }

  function tick() {
    if (++index >= input.length) {
      return;
    }

    encodeAndSendKey(input[index]);
    setTimeout(tick, delay);
  }

  showGui();
})();

Here's a minified bookmarklet based on @rmb122 's answer

javascript:(function(){var e,t,n,a,i,l,o="",r="100",s=-1,p="00novnccustompastetool0947-maindiv",u="00novnccustompastetool0947-textinput",d="00novnccustompastetool0947-numinput";function c(e){e.preventDefault();var t=document.getElementById(p);document.body.removeChild(t)}let y=document.querySelector("iframe").contentDocument.getElementById("noVNC_keyboardinput"),m=e=>y.dispatchEvent(new KeyboardEvent("keydown",{key:e}));function $(){!(++s>=o.length)&&(!function e(t){if("\r"!==t){if(""===t){m("Tab");return}if("\n"===t){m("Enter");return}m(t)}}(o[s]),setTimeout($,r))}(e=document.createElement("div")).id=p,e.style.position="fixed",e.style.zIndex="9999999999",e.style.backgroundColor="rgb(221 221 221 / 90%)",e.style.top="0",e.style.left="0",e.style.right="0",e.style.padding="8px",e.style.height="168px",e.innerHTML="<b>Paste your text</b><br>Note: Use your mouse for copying and pasting because the KVM console snatches all input and this is the only sane work-around.<br>",(t=document.createElement("textarea")).id=u,t.onkeydown=function e(t){t.preventDefault()},t.style.display="block",t.style.width="100%",t.style.marginBottom="8px",(n=document.createElement("label")).innerHTML="Per-key delay in ms:&nbsp;",n.title="Sending keys too fast can cause issues (such as skipped keys); the delay helps alleviate this.",(a=document.createElement("input")).title=n.title,a.setAttribute("type","number"),a.setAttribute("min","1"),a.setAttribute("max","100000"),a.value=r,a.id=d,(i=document.createElement("button")).innerText="Paste",i.onclick=function e(t){if(t.preventDefault(),o=document.getElementById(u).value,!(r=Number(document.getElementById(d).value)))return alert("Cannot proceed: delay number is invalid."),c();c(t),setTimeout($,500)},i.style.margin="8px",(l=document.createElement("button")).innerText="Cancel",l.onclick=c,e.append(t),e.append(n),e.append(a),e.append(document.createElement("br")),e.append(l),e.append(i),document.body.append(e)})();