noVNC Paste Tampermonkey script.

noVNCPaste.user.js

// ==UserScript==
// @name         noVNC Paste
// @namespace    http://tampermonkey.net/
// @version      0.2a
// @description  Pastes text into a noVNC window
// @author       You
// @match        */console*
// @require http://code.jquery.com/jquery-3.3.1.min.js
// @grant        none
// ==/UserScript==

;(function() {
    'use strict'

    var XK_Shift_L = 0xffe1
    // Find and create the copy and paste location
    window.paste = function() {
        var text = prompt('Please enter text to paste:', '')
        sendString(text)
    }
    window.sendString = function(str) {
        f(str.split(''))
        function f(t) {
            var character = t.shift()
            var i = []
            var code = character.charCodeAt()
            var needs_shift = character.match(/[A-Z!@#$%^&*()_+{}:\"<>?~|]/)
            if (needs_shift) {
                rfb.sendKey(XK_Shift_L, 1)
            }
            rfb.sendKey(code, 1)
            rfb.sendKey(code, 0)
            if (needs_shift) {
                rfb.sendKey(XK_Shift_L, 0)
            }

            if (t.length > 0) {
                setTimeout(function() {
                    f(t)
                }, 10)
            }
        }
    }
    $(document).ready(function() {
        var ctrlDown = false,
            ctrlKey = 17,
            cmdKey = 91,
            vKey = 86,
            cKey = 67

        $(document)
            .keydown(function(e) {
                if (e.keyCode == ctrlKey || e.keyCode == cmdKey) ctrlDown = true
            })
            .keyup(function(e) {
                if (e.keyCode == ctrlKey || e.keyCode == cmdKey)
                    ctrlDown = false
            })

        $('.no-copy-paste').keydown(function(e) {
            if (ctrlDown && (e.keyCode == vKey || e.keyCode == cKey))
                return false
        })

        // Document Ctrl + C/V
        $(document).keydown(function(e) {
            if (ctrlDown && e.keyCode == vKey)
                console.log('Document catch Ctrl+V')
                paste()
                ctrlDown = false
        })
    })

    $('#noVNC_screen').prepend(
        "<div style='padding:20px;'><button onclick='javascript:paste();'>Click to Paste Text</button></div>"
    )
})()

This is just a small tampermonkey script to add a button at the top of a noVNC session to paste in text to the terminal.