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); }
})();

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)})();