see comments

cse143_hw_shower.js

// Visit courses.cs.washington.edu/courses/cse143/13au/homework.shtml or 
// https://courses.cs.washington.edu/courses/cse143/13au/homework.shtml and run 
// this snippet of JavaScript to display otherwise hidden homework assignments.
//
// Note that the revealed assignments are probably old ones. 

(function () {
    "use strict";

    // display commented content
    var newHTML = document.getElementsByTagName('html')[0].innerHTML;
    document.getElementsByTagName('html')[0].innerHTML = newHTML.replace(/(<!--)|(-->)/g, '');

    // display elements with 'delayed' class
    var delayedElements = document.getElementsByClassName('delayed');
    for (var i = 0; i < delayedElements.length; i++) {
        delayedElements[i].setAttribute('style', 'display: block');
    }
}());