Updating text box values on DOM elements in React using dispatchEvent - login example

setting_react_text_box_value_via_dom.js

function simulate_input_event(element) {
    var event = new Event('input', { bubbles: true });
    element.dispatchEvent(event);
}

document.forms[0][0].value='username';
simulate_input_event(document.forms[0][0]);

document.forms[0][1].value='password';
simulate_input_event(document.forms[0][1]);

document.forms[0][2].click() //click the login button