Southwest Flight Auto Check-In

I've taken a few flights on Southwest over the last couple of months and have another coming up.
One thing I don't particularly enjoy is the day-before-flight ritual of watching the clock, waiting to click the check-in button so I can get a decent seat.  The early bird option at $12.95 each way doesn't seem like a great value, and besides, I'm too cheap anyway.

Not long ago there was a great website that allowed users to enter Southwest flight info and would automatically check them in for their flight. Southwest, not surprising, put an end to that. :(  With the success of my Pandora user script, I thought another go was in order.

Last night I spent about an hour putting this little user script together that *should* work. I tested all the way up to the actual printing your boarding pass page.  I saved a copy of all the check-in pages the last time I flew Southwest in anticipation of someday writing a script like this.  From those saved pages, I think I'm doing everything correctly.  Have to wait until my actual flight to find out - wish me luck.

The magic happens after you input your flight information and click the 'Check In' button.  The script keys off the oops message Southwest provides and inserts inputs for the date/time of your flight.  Make sure the oops is because you're over the 24-hour period and not for some other reason.

Date/Time Input

Any date/time validation errors are displayed.

Validation Error

One thing to note is that the script limits you to only checking in for a flight that is at most, 24 days away.  I did this because the timeout argument to window.setTimeout() is a signed 32-bit integer.  Any good computer science major will know that caps the max timeout to 2^31 - 1 msec, a little over 24 days.  I could have chained timeouts to allow for any future date, but 24 days is plenty for me.

The Final Countdown!

Countdown

Once the countdown is finished, the script will automatically click the 'Check In' button.  From there it will select all passengers and click the print boarding passes button.  You'll have to trust me on that last part!

	// ==UserScript==
	// @name Southwest Auto Check-In
	// @namespace http://dbknickerbocker.blogspot.com
	// @description Automatically check-in for Southwest flights
	// @include http://southwest.com/flight/retrieveCheckinDoc*
	// @include http://www.southwest.com/flight/retrieveCheckinDoc*
	// @include http://southwest.com/flight/selectPrintDocument*
	// @include http://www.southwest.com/flight/selectPrintDocument*
	// @updateURL https://gist.github.com/dbknickerbocker/5730976/raw/southwest.user.js
	// @author David B. Knickerbocker
	// @version 0.3
	// ==/UserScript==
	var SECOND_IN_MSEC = (1000);
	var MINUTE_IN_MSEC = (SECOND_IN_MSEC * 60);
	var HOUR_IN_MSEC = (MINUTE_IN_MSEC * 60);
	var DAY_IN_MSEC = (HOUR_IN_MSEC * 24);
	var TIMEOUT_MAX_MSEC = (DAY_IN_MSEC * 24);
	function southwestCheckInForm() {
	return document.getElementById('itineraryLookup');
	}
	function submitSouthwestCheckInForm() {
	try {
	southwestCheckInForm().submit();
	} catch (exception) {
	alert("Unknown error has occured - You're on your own! :" + exception.message);
	}
	}
	function countdownDiv() {
	return document.getElementById('countdown');
	}
	function insertBreak(element) {
	element.appendChild(document.createElement('br'));
	}
	function insertText(element, text) {
	element.appendChild(document.createTextNode(text));
	}
	function insertTextWithBoldStyle(element, text) {
	var span = document.createElement('span');
	span.style.fontWeight = 'bold';
	insertText(span, text);
	element.appendChild(span);
	}
	function removeAllChildrenFromElement(element) {
	while (element.firstChild) {
	element.removeChild(element.firstChild);
	}
	}
	function zeroPad(value) {
	return (value < 10) ? '0' + value : value;
	}
	function displayCountdown(checkInDate) {
	try {
	var countdown = countdownDiv();
	removeAllChildrenFromElement(countdown);
	var timeRemainingMsec = checkInDate - new Date();
	if (timeRemainingMsec <= 0) {
	insertTextWithBoldStyle(countdown, 'Checking in now...');
	insertBreak(countdown);
	return;
	}
	var days = Math.floor(timeRemainingMsec / DAY_IN_MSEC);
	var hours = Math.floor(timeRemainingMsec / HOUR_IN_MSEC) % 24;
	var minutes = Math.floor(timeRemainingMsec / MINUTE_IN_MSEC) % 60;
	var seconds = Math.floor(timeRemainingMsec / SECOND_IN_MSEC) % 60;
	insertBreak(countdown);
	insertTextWithBoldStyle(countdown, 'Check-in time: ');
	insertText(countdown, checkInDate.toString());
	insertBreak(countdown);
	insertTextWithBoldStyle(countdown, 'Time remaining until automatic check-in: ');
	insertText(countdown, zeroPad(days) + ' DAY ' + zeroPad(hours) + ' HRS ' + zeroPad(minutes) + ' MIN ' + zeroPad(seconds) + ' SEC');
	insertBreak(countdown);
	insertBreak(countdown);
	} catch (exception) {
	alert("Unknown error has occured - You're on your own! :" + exception.message);
	}
	}
	function elementByIdValueAsInteger(id) {
	return parseInt(document.getElementById(id).value, 10);
	}
	function getFlightDate() {
	var month = elementByIdValueAsInteger('month-input') - 1;
	var day = elementByIdValueAsInteger('day-input');
	var year = elementByIdValueAsInteger('year-input');
	var hours = elementByIdValueAsInteger('hour-input');
	var minutes = elementByIdValueAsInteger('minute-input');
	var seconds = elementByIdValueAsInteger('second-input');
	var flightDate = new Date(year, month, day, hours, minutes, seconds, 0);
	if ((flightDate.getMonth() != month) || (flightDate.getDate() != day) || (flightDate.getFullYear() != year) ||
	(flightDate.getHours() != hours) || (flightDate.getMinutes() != minutes) || (flightDate.getSeconds() != seconds)) {
	return null;
	}
	return flightDate;
	}
	function displayUnderOneHourError() {
	insertAutoCheckInFormWithError('Unable to check-in when flight is within one hour.');
	}
	function displayInvalidDateError() {
	insertAutoCheckInFormWithError('Invalid Date!');
	}
	function displayMaxTimeoutError() {
	var maxFlightDateToSatisfyMaxTimeout = new Date(new Date().getTime() + TIMEOUT_MAX_MSEC + DAY_IN_MSEC);
	insertAutoCheckInFormWithError('Your flight must be before: ' + maxFlightDateToSatisfyMaxTimeout);
	}
	function displayFlightInPastError(flightDate) {
	insertAutoCheckInFormWithError('You already missed your flight: ' + flightDate);
	}
	function startAutoCheckInCountdown() {
	try {
	var flightDate = getFlightDate();
	if (flightDate === null) {
	displayInvalidDateError();
	return;
	}
	var timeRemainingToFlightMsec = (flightDate - new Date());
	if (timeRemainingToFlightMsec < 0) {
	displayFlightInPastError(flightDate);
	return;
	}
	if (timeRemainingToFlightMsec <= HOUR_IN_MSEC) {
	displayUnderOneHourError();
	return;
	}
	if (timeRemainingToFlightMsec <= DAY_IN_MSEC) {
	submitSouthwestCheckInForm();
	return;
	}
	var timeRemainingToCheckInMsec = timeRemainingToFlightMsec - DAY_IN_MSEC;
	if (timeRemainingToCheckInMsec > TIMEOUT_MAX_MSEC) {
	displayMaxTimeoutError();
	return;
	}
	var checkInDate = new Date(flightDate.getTime() - DAY_IN_MSEC);
	window.setTimeout(submitSouthwestCheckInForm, timeRemainingToCheckInMsec);
	window.setInterval(function () {
	displayCountdown(checkInDate);
	}, SECOND_IN_MSEC);
	} catch (exception) {
	alert("Unknown error has occured - You're on your own! :" + exception.message);
	}
	}
	function insertInput(element, id, value, length) {
	var input = document.createElement('input');
	input.id = id;
	input.type = 'text';
	input.maxLength = length;
	input.size = length;
	input.value = value;
	input.setAttribute('onfocus', "if (this.value === '" + value + "') { this.value = ''; }");
	element.appendChild(input);
	}
	function insertLabel(element, text, id) {
	var label = document.createElement('label');
	label.setAttribute('for', id);
	label.textContent = text;
	element.appendChild(label);
	}
	function insertH4(element, text) {
	var h4 = document.createElement('h4');
	h4.textContent = text;
	element.appendChild(h4);
	return h4;
	}
	function insertH4WithColor(element, text, color) {
	var h4 = insertH4(element, text);
	h4.style.color = color;
	}
	function createAutoCheckInForm() {
	var autoCheckInForm = document.createElement('form');
	autoCheckInForm.setAttribute('method', 'POST');
	insertH4(autoCheckInForm, 'When is your flight?');
	insertBreak(autoCheckInForm);
	insertLabel(autoCheckInForm, 'Date: ', 'month-input');
	insertInput(autoCheckInForm, 'month-input', 'mm', '2');
	insertText(autoCheckInForm, '/');
	insertInput(autoCheckInForm, 'day-input', 'dd', '2');
	insertText(autoCheckInForm, '/');
	insertInput(autoCheckInForm, 'year-input', 'yyyy', '4');
	insertBreak(autoCheckInForm);
	insertLabel(autoCheckInForm, 'Time (24 hr): ', 'hour-input');
	insertInput(autoCheckInForm, 'hour-input', 'hh', '2');
	insertText(autoCheckInForm, ':');
	insertInput(autoCheckInForm, 'minute-input', 'mm', '2');
	insertText(autoCheckInForm, ':');
	insertInput(autoCheckInForm, 'second-input', 'ss', '2');
	insertBreak(autoCheckInForm);
	insertBreak(autoCheckInForm);
	var startAutoCheckInButton = document.createElement('input');
	startAutoCheckInButton.id = 'auto-check-in-button';
	startAutoCheckInButton.type = 'button';
	startAutoCheckInButton.value = 'Start Auto Check-In';
	startAutoCheckInButton.addEventListener('click', startAutoCheckInCountdown, true);
	autoCheckInForm.appendChild(startAutoCheckInButton);
	return autoCheckInForm;
	}
	function insertChildBefore(child, element) {
	element.parentNode.insertBefore(child, element);
	}
	function removePreviousCountdownDiv() {
	var countdown = countdownDiv();
	if ((countdown !== null) && (countdown.parentNode !== null)) {
	countdown.parentNode.removeChild(countdown);
	}
	}
	function insertCountdownDivWithElements(elements) {
	removePreviousCountdownDiv();
	var countdownDiv = document.createElement('div');
	countdownDiv.id = 'countdown';
	countdownDiv.style.backgroundColor = '#F3F5FF';
	countdownDiv.style.borderRadius = '10px';
	countdownDiv.style.padding = '20px';
	for (var i = 0; i < elements.length; ++i) {
	countdownDiv.appendChild(elements[i]);
	}
	insertChildBefore(countdownDiv, southwestCheckInForm());
	}
	function createErrorNode(error) {
	var div = document.createElement('div');
	insertH4WithColor(div, error, 'red');
	insertBreak(div);
	return div;
	}
	function insertAutoCheckInFormWithError(error) {
	insertCountdownDivWithElements([createErrorNode(error), createAutoCheckInForm()]);
	}
	function insertAutoCheckInForm() {
	insertCountdownDivWithElements([createAutoCheckInForm()]);
	}
	function countdownDivPresent() {
	return (countdownDiv() !== null);
	}
	function checkForDepartureTimeOops() {
	try {
	var errorsUl = document.querySelector('ul#errors');
	if (errorsUl === null) {
	return;
	}
	var errors = errorsUl.getElementsByTagName('li');
	for (var i = 0; i < errors.length; ++i) {
	if (errors[i].textContent.indexOf('more than 24 hours prior') >= 0) {
	insertAutoCheckInForm();
	break;
	}
	}
	} catch (exception) {
	alert("Unknown error has occured - You're on your own! :" + exception.message);
	}
	}
	function selectAllPassengers() {
	var inputs = document.getElementsByTagName('input');
	for (var i = 0; i < inputs.length; ++i) {
	var input = inputs[i];
	if (input.getAttribute('type') == 'checkbox') {
	input.checked = true;
	}
	}
	}
	function printDocuments() {
	try {
	var printButton = document.getElementById('printDocumentsButton');
	if (printButton === null) {
	return;
	}
	selectAllPassengers();
	printButton.click();
	} catch (exception) {
	alert("Unknown error has occured - You're on your own! :" + exception.message);
	}
	}
	if (document.location.href.indexOf('retrieveCheckinDoc') >= 0) {
	if (!countdownDivPresent()) {
	checkForDepartureTimeOops();
	}
	} else if (document.location.href.indexOf('selectPrintDocument') >= 0) {
	printDocuments();
	}

view raw southwest.user.js hosted with ❤ by GitHub

I only tested the script in Chrome, but Firefox should work with the Greasemonkey plugin.  To install, just drag-and-drop the file into the Chrome Extensions window.