DigitalOcean_NoVNC_Paste.js

// This will open up a prompt for text to send to a console session on digital ocean
//  Useful for long passwords
(function () {        
        var t = prompt("Enter text to be sent to console, (This wont send the enter keystroke)").split("");
        function f() {
                
                var character = t.shift();
                var i=[];
                var code = character.charCodeAt();
                var needs_shift = "!@#$%^&*()_+{}:\"<>?~|".indexOf(character) !== -1
                var shift = XK_Shift_L; // To help with minification
                function key(keycode, down) {
                        i=i.concat(RFB.messages.keyEvent(keycode, down));
                }
                
                if (needs_shift) {
                        key(shift,1);
                }
                key(code,1);
                key(code,0);
                if (needs_shift) {
                        key(shift,0);
                }
                rfb._sock.send(i);
                
                if (t.length > 0) {
                        setTimeout(f, 10);
                }
        }
        f();
})();

// Minified version:
!function(){function t(){function n(t,e){s=s.concat(RFB.messages.keyEvent(t,e))}var o=e.shift(),s=[],i=o.charCodeAt(),c=-1!=='!@#$%^&*()_+{}:"<>?~|'.indexOf(o),r=XK_Shift_L;c&&n(r,1),n(i,1),n(i,0),c&&n(r,0),rfb._sock.send(s),e.length>0&&setTimeout(t,10)}var e=prompt("Enter text to be sent to console, (This wont send the enter keystroke)").split("");t()}();


// This is an alternate version that will open a box on ctrl+shift+v or command+shift+v
// this version might work better on browsers that block prompt from console
(function(){
  var shift_down = false;
  var ctrl_down = false;
  var super_down = false;
  var v_down = false;
  $(document).keydown(function(e) { 
    if      (e.which == 17) { ctrl_down = true; }
    else if (e.which == 16) { shift_down = true; }
    else if (e.which == 91) { super_down = true; }
    else if (e.which == 86)  { v_down     = true; }
    if (v_down  && shift_down && (super_down || ctrl_down) ) { 
        ctrl_down = false;
        shift_down = false;
        super_down = false;           
        var t = prompt("Enter text to be sent to console, (This wont send the enter keystroke)").split("");
        function f() {
                var character = t.shift();
                var i=[];
                var code = character.charCodeAt();
                var needs_shift = "!@#$%^&*()_+{}:\"<>?~|".indexOf(character) !== -1
                var shift = XK_Shift_L; // To help with minification
                function key(keycode, down) {
                        i=i.concat(RFB.messages.keyEvent(keycode, down));
                }
                
                if (needs_shift) {
                        key(shift,1);
                }
                key(code,1);
                key(code,0);
                if (needs_shift) {
                        key(shift,0);
                }
                rfb._sock.send(i);
                
                if (t.length > 0) {
                        setTimeout(f, 10);
                }
        }
        setTimeout(f, 10);
    }
  });
  $(document).keyup(function(e) { 
    if      (e.which == 17) { ctrl_down  = false; }
    else if (e.which == 16) { shift_down = false; }
    else if (e.which == 91) { super_down = false; }
    else if (e.which == 86) { v_down     = false; }
  });
})();

// Minified version:
(function(){var d=!1,b=!1,c=!1,f=!1;$(document).keydown(function(a){17==a.which?b=!0:16==a.which?d=!0:91==a.which?c=!0:86==a.which&&(f=!0);if(f&&d&&(c||b)){c=d=b=!1;var g=prompt("Enter text to be sent to console, (This wont send the enter keystroke)").split(""),h=function(){function a(b,c){d=d.concat(RFB.messages.keyEvent(b,c))}var e=g.shift(),d=[],b=e.charCodeAt(),e=-1!=='!@#$%^&*()_+{}:"<>?~|'.indexOf(e),c=XK_Shift_L;e&&a(c,1);a(b,1);a(b,0);e&&a(c,0);rfb._sock.send(d);0<g.length&&setTimeout(h,10)};
setTimeout(h,10)}});$(document).keyup(function(a){17==a.which?b=!1:16==a.which?d=!1:91==a.which?c=!1:86==a.which&&(f=!1)})})();

thanks all! definitely works for me, I also had to increase the timeout, as elmehalawi mentioned, I used Chrome

If characters are sent in the wrong order, watzon's script and increasing the timeout. This worked for me.