var NextButton, tStart, tEnd;

document.addEventListener("DOMContentLoaded", ()=> {
    NextButton = document.getElementById('next-btn');
    dRT = document.getElementById('dRT')
    tStart = new Date();
}) 

function endTrial() {
    tEnd = new Date();
    dRT.value =( tEnd - tStart)/1000;
    NextButton.click();
}