tampermonkey user script that saves and autofills DOB and USC details in dr plano booking

drplanoAutoDOBUSC.js

// ==UserScript==
// @name         Dr Plano DOB USC
// @namespace    http://tampermonkey.net/
// @version      0.2
// @description  Autofill DOB and USC in Dr Plano Booking
// @author       https://github.com/brett-schneider
// @include      /^https?://.*drpCourseId=\d*
// @match        *?drpCourseId=*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=tampermonkey.net
// @grant        GM_getValue
// @grant        GM_setValue
// ==/UserScript==

(function() {
    'use strict';
    const targetNode = document.getElementsByTagName('body')[0];
    const observer = new MutationObserver(callback);
    const config = { attributes: false, childList: true, subtree: true };
    // const config = { attributes: true, childList: true, subtree: true };
    observer.observe(targetNode, config);
})();

function cc(a) {
    // console.log(a);
}

function updateData(e) {
    cc("fired: updateData");
    let dob = GM_getValue(e.target.value);
    let usc = GM_getValue("usc_"+e.target.value);
    cc("values: "+dob+" / "+usc);
    if (dob && document.getElementsByName("date-of-birth")[0]) document.getElementsByName("date-of-birth")[0].setAttribute("value",dob);
    if (usc && document.getElementsByName("participant-tariff-id")[0] && document.getElementsByName("participant-additional-field-value")[0]) {
        document.getElementsByName("participant-tariff-id")[0].setAttribute("value","155589630");
        document.getElementsByName("participant-additional-field-value")[0].setAttribute("value",usc);
    }
};

function saveData(e) {
    if (document.getElementsByName("email")[0]) {
        cc("saving for: "+document.getElementsByName("email")[0].value);
        if (document.getElementsByName("date-of-birth")[0]) {
            GM_setValue(document.getElementsByName("email")[0].value, document.getElementsByName("date-of-birth")[0].value);
            cc("dob: "+document.getElementsByName("date-of-birth")[0].value);
        }
        if (document.getElementsByName("participant-additional-field-value")[0]) {
            GM_setValue("usc_"+document.getElementsByName("email")[0].value, document.getElementsByName("participant-additional-field-value")[0].value);
            cc("usc: "+document.getElementsByName("participant-additional-field-value")[0].value);
        }
    }
};

function findLMNTs(ruth) {
    cc("finding elements in: "+ruth+" ("+(typeof ruth)+")");
    cc("querySelector: "+(typeof ruth.querySelector));
    if (typeof ruth.querySelector !== 'undefined') {
        let email = ruth.querySelector('input[name="email"]');
        let form = ruth.querySelector('form');
        if (email) {
            email.addEventListener('input', updateData);
            cc("mail found");
        }
        if (form) {
            form.addEventListener('submit', saveData);
            cc("form found");
        }
    }
}

function callback(mutationList, observer) {
    mutationList.forEach( (mutation) => {
        switch(mutation.type) {
            case 'childList':
                cc("nodes added");
                cc(mutation.addedNodes);
                mutation.addedNodes.forEach(x => cc(x));
                mutation.addedNodes.forEach(x => findLMNTs(x));
                break;
        }
    });
}