Possibly Encrypted "a href" Links at TripAdvisor - html

Question

On TripAdvisor.com attraction pages, the link to the website of the attraction seems to be encrypted in some way. Here is an example:
<span class="taLnk hvrIE6" onclick="ta.trackEventOnPage('AttractionContactInfo',
'Website', 1755031, 1); ta.util.cookie.setPIDCookie(15190);
ta.call('ta.util.link.targetBlank', event, this
{'aHref':'LqMWJQiMnYQQoqnQQxGEcQQoqnQQbIIEJnISiCQQoqnQQeVsSVuWJQzZYUWJQpEcYGII26XombQQoqnQQQQoqnqgoqnQQQQoqnQQQQoqnQQQQoqnqgoqnQQQQoqnQQEVMIGVJIEV9pCyTptGiuQQoqnQQQQoqnxioqnQQQQoqnQQniaWJQzhY3mJnJUUJXomoAvoJJB', 'isAsdf':true})">
Website
</span>
How is this link made and what might be the reason for doing so?

Answer 1

The aHref value is an encrypted URL that can be decrypted using the TripAdvisor asdf() Javascript function. For example, using the Javascript console in Firefox, type the following while at www.tripadvisor.com:
console.log(asdf('encrypted URL'));
An example:
console.log(asdf('LqMWJQzZYUWJQpEcYGII26XombQQoqnQQQQoqnqgoqnQQQQoqnQQQQoqnQQQQoqnqgoqnQQQQoqnQQuuuQQoqnQQQQoqnxioqnQQQQoqnQQEitVuiiMqxQQoqnQQQQoqnxioqnQQQQoqnQQniaQQoqnQQQQoqnqgoqnQQQQoqnQQVCQQoqnQQQQoqnqgoqnQQQQoqnQQIGVQQoqnQQQQoqnqHoqnQQQQoqnQQnJEcgcVQQoqnQQQQoqnqHoqnQQQQoqnQQCVuQQoqnQQQQoqnqHoqnQQQQoqnQQgiE9QQoqnQQQQoqnqgoqnQQQQoqnQQMSCSCyQQoqnQQQQoqnqgoqnQQQQoqnQQHVaVcaJCtQQoqnQQQQoqnqHoqnQQQQoqnQQHJEWJQzhYUMo3JKHkmKnVmJVdUB'));
Gives the following (append to http://tripadvisor.com):
/ShowUrl-a_partnerKey.1-a_url.http%253A__5F____5F__2F__5F____5F____5F____5F__2F__5F____5F__www__5F____5F__2E__5F____5F__rosewoodhotels__5F____5F__2E__5F____5F__com__5F____5F__2F__5F____5F__en__5F____5F__2F__5F____5F__the__5F____5F__2D__5F____5F__carlyle__5F____5F__2D__5F____5F__new__5F____5F__2D__5F____5F__york__5F____5F__2F__5F____5F__dining__5F____5F__2F__5F____5F__bemelmans__5F____5F__2D__5F____5F__bar-a_urlKey.1d56a0b730ce3ae41.html
The source of the TripAdvisor asdf() function:
function asdf(d) {
var h = {
"": ["&", "=", "p", "6", "?", "H", "%", "B", ".com", "k", "9", ".html", "n", "M", "r", "www.", "h", "b", "t", "a", "0", "/", "d", "O", "j", "http://", "_", "L", "i", "f", "1", "e", "-", "2", ".", "N", "m", "A", "l", "4", "R", "C", "y", "S", "o", "+", "7", "I", "3", "c", "5", "u", 0, "T", "v", "s", "w", "8", "P", 0, "g", 0],
q: [0, "__3F__", 0, "Photos", 0, "https://", ".edu", "*", "Y", ">", 0, 0, 0, 0, 0, 0, "`", "__2D__", "X", "<", "slot", 0, "ShowUrl", "Owners", 0, "[", "q", 0, "MemberProfile", 0, "ShowUserReviews", '"', "Hotel", 0, 0, "Expedia", "Vacation", "Discount", 0, "UserReview", "Thumbnail", 0, "__2F__", "Inspiration", "V", "Map", ":", "#", 0, "F", "help", 0, 0, "Rental", 0, "Picture", 0, 0, 0, "hotels", 0, "ftp://"],
x: [0, 0, "J", 0, 0, "Z", 0, 0, 0, ";", 0, "Text", 0, "(", "x", "GenericAds", "U", 0, "careers", 0, 0, 0, "D", 0, "members", "Search", 0, 0, 0, "Post", 0, 0, 0, "Q", 0, "$", 0, "K", 0, "W", 0, "Reviews", 0, ",", "__2E__", 0, 0, 0, 0, 0, 0, 0, "{", "}", 0, "Cheap", ")", 0, 0, 0, "#", ".org"],
z: [0, "Hotels", 0, 0, "Icon", 0, 0, 0, 0, ".net", 0, 0, "z", 0, 0, "pages", 0, "geo", 0, 0, 0, "cnt", "~", 0, 0, "]", "|", 0, "tripadvisor", "Images", "BookingBuddy", 0, "Commerce", 0, 0, "partnerKey", 0, "area", 0, "Deals", "from", "\\", 0, "urlKey", 0, "'", 0, "WeatherUnderground", 0, "MemberSign", "Maps", 0, "matchID", "Packages", "E", "Amenities", "Travel", ".htm", 0, "!", "^", "G"]
};
var b = "";
for (var a = 0; a < d.length; a++) {
var j = d.charAt(a);
var f = j;
if (h[j] && a + 1 < d.length) {
a++;
f += d.charAt(a)
} else {
j = ""
}
var g = getOffset(d.charCodeAt(a));
if (g < 0 || typeof h[j][g] == "String") {
b += f
} else {
b += h[j][g]
}
}
return b}
And the source of the getOffset() function referred to from asdf():
function getOffset(a) {
if (a >= 97 && a <= 122) {
return a - 61
}
if (a >= 65 && a <= 90) {
return a - 55
}
if (a >= 48 && a <= 71) {
return a - 48
}
return -1}

Answer 2

It could possibly be done to prevent screen scrapers and robots from automatically generating traffic to other sites.
Some server side code generated this and it's used for tracking, statistics and setting some cookie values etc.
Trip advisor will be able to determine what links were clicked and also share this information with the attraction (i.e. 50 people accessed your website from the Trip Advisor website etc)
Hope it's useful