How to Paste code to NoVNC.

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 () {        
    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);
            }
        }
    }
})();


# Minified Version:
(function(){window.sendString=function(a){function b(c){var d=c.shift(),g=d.charCodeAt(),h=d.match(/[A-Z!@#$%^&*()_+{}:\"<>?~|]/);h&&rfb.sendKey(XK_Shift_L,1),rfb.sendKey(g,1),rfb.sendKey(g,0),h&&rfb.sendKey(XK_Shift_L,0),0<c.length&&setTimeout(function(){b(c)},10)}b(a.split(""))}})();

Did you try:

sendString("mychars\r\nother chars");  # Maybe your client accepts \r\n as new line. 

Yup, tried \r, \n, \r\n.
And even tried rfb.sendKey(13, true). None worked, it feels like noVNC don't accept new lines in this function or something.

(function () {
    const XK_Shift_L = 65505; // https://docs.rs/x11-dl/1.0.1/x11_dl/keysym/constant.XK_Shift_L.html      
    window.sendString = function (str, pressOnly) {
        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,null,1);
            }
            rfb.sendKey(code,1);
            !pressOnly && rfb.sendKey(code,null,0);
            if (needs_shift) {
                rfb.sendKey(XK_Shift_L,null,0);
            }
            
            if (t.length > 0) {
                setTimeout(function() {f(t);}, 10);
            }
        }
    }
})(); 

My version of rfb needs 3 params to sendKey