Homestuck Pesterlog Simulator

// ==UserScript==
// @name         Homestuck Pesterlog Simulatior
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Simulates the scrolling pesterlog.
// @author       Cal Kalum
// @match        https://www.homestuck.com/story/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';
    let pElements = document.getElementsByTagName('p');
    console.log(pElements);
    let spans = [];
    for(let i = 0; i < pElements.length; i++){
        let spancheck = pElements[i].children;
        for(let j = 0; j < spancheck.length; j++){
            console.log(spancheck[j]);
            if(spancheck[j].tagName === "SPAN"){
                spans.push(spancheck[j]);
                spans[spans.length - 1].style.transition = "0.3s";
                spans[spans.length - 1].style.opacity = 0;
            }
        }
    }
    console.log(spans);
    // Your code here...
    let spanIndex = 0;
    document.addEventListener("keydown", function (e) {
        if(e.key ==='Enter'){
            spans[spanIndex].style.opacity = 1;
            spanIndex++;
        }
    });
})();