46 lines
1.7 KiB
JavaScript
46 lines
1.7 KiB
JavaScript
"use strict";
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const getElement = selector => document.querySelector(selector);
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document.addEventListener("DOMContentLoaded", () => {
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getElement("#countdown").addEventListener("click", () => {
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const eventName = getElement("#event").value;
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const eventDateString = getElement("#date").value;
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const messageLbl = getElement("#message");
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// make sure user entered event name and date
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if (eventName.length == 0 || eventDateString.length == 0) {
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messageLbl.textContent = "Please enter both a name and a date.";
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return;
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}
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// make sure date is valid
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const eventDate = new Date(eventDateString);
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if (eventDate == "Invalid Date") {
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messageLbl.textContent = "Please enter a valid date.";
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return;
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}
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// calculate days
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const today = new Date();
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const msFromToday = eventDate.getTime() - today.getTime();
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const msForOneDay = 24 * 60 * 60 * 1000; // hrs * mins * secs * milliseconds
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const daysToDate = Math.ceil( msFromToday / msForOneDay );
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// create and display message
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let msg = "";
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const date = eventDate.toDateString();
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if (daysToDate == 0) {
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msg = `Hooray! Today is ${eventName}! (${date})`;
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} else if (daysToDate > 0) {
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msg = `${daysToDate} day(s) until ${eventName}! (${date})`;
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} else if (daysToDate < 0) {
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msg = `${eventName} happened ${Math.abs(daysToDate)}
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day(s) ago. (${date})`;
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}
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messageLbl.textContent = msg;
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});
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// set focus on first text box
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getElement("#event").focus();
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}); |