Web sites that 'lock you in' - why NASA?

JohnD · Post by **JohnD** » Wed Sep 20, 2006 8:16 pm

All,
I've always despised those websites that 'lock you in', that prevent you using the 'back' button to return whence you came. They are usually commercial sites, that I presume do this in the vain hope that this will induce you to buy something. Vain indeed!

Today's APOD of the new Truss on the ISS includes a hyperlink to a NASA page about the ISS and the truss structure. Once there, you are locked in. See: http://www.nasa.gov/mission_pages/stati ... s/its.html

It's easy enough to get out, or to just close that window, but why do they do this? It's not as if NASA has anything to sell.

John

craterchains · Post by **craterchains** » Wed Sep 20, 2006 8:47 pm

dont yah just hate that?

gerrrrrrrrrrrrrr

Norval

orin stepanek · Post by **orin stepanek** » Wed Sep 20, 2006 9:06 pm

On My search I could right click on my search and drop-down would let me click out of picture without having to close window. On Google I had to multiple click on arrow to get out. It can be pretty frustrating at times.

Orin

BMAONE23 · Post by **BMAONE23** » Wed Sep 20, 2006 9:40 pm

its not a true lock in only a second window being activated

JohnD · Post by **JohnD** » Wed Sep 20, 2006 10:19 pm

Thanks, Orin.
And; right click and select 'Google search' to force the window to go to Google.

BMA,
What do you mean? When going to that page from APOD, it goes through a page whose URL starts "www.spaceflight......" and then loads the Truss page. Too quickly for me to read. The back key takes you the first 'spaceflight' page, which then reloads the Truss page automatically. That's locked-in in my country.

But this is all 'How?'
I want to know 'Why?'

John

BMAONE23 · Post by **BMAONE23** » Thu Sep 21, 2006 1:13 am

I didn't read your primary post thoroughly enough to understand the point you were making. I just tried it as described and had similar results to yours. You do get locked in. Don't know why though.

iamlucky13 · Post by **iamlucky13** » Thu Sep 21, 2006 7:37 pm

I do some web development, and I see this a lot. For whatever reason (and there are many legitimate possibilities, from restructuring the website to monitoring traffic), they are using a meta redirect:

Code: Select all

<META CONTENT="0;URL=http://www.nasa.gov/mission_pages/station/structure/elements/its.html" HTTP-EQUIV="REFRESH">

It's actually a rather poor method in most cases and generally shouldn't be used. A server-side redirect is really the best way because it doesn't "break the back button" as we say and search engines will update their results.

Essentially, APOD copied a link to a page on the NASA spaceflight site. The link pointed to another NASA spaceflight page, but that page isn't actually where the info is. Probably it was there and was later moved to the NASA main site. To keep viewers who followed a link or bookmarked the page from getting a "404: Page not found" error, they inserted the meta tag that tells the browser to load the page on the NASA main site.

So your browser has actually visited three pages (apod, spaceflight.nasa.gov, and nasa.gov). When you click the back button, it goes back the spaceflight page that still has the meta tag, which causes the browser to once again jump forward. Had they used a server side redirect ("301: permanent redirect" is the best option) your browser would only remember the two pages that actually have information. Unfortunately that requires changing some things on the server instead of adding that one line of code to the intermediate webpage, so they probably did it to keep things quick and organized.

You can doubleclick the back button and it will jump back two pages before the middle page finishes loading. Meta tags aren't recognized until the page loads.

It's partially the APOD author's fault for copying the link (which points to spaceflight.nasa.gov) instead of loading the actual page and copying the address from there (http://www.nasa.gov).

JohnD · Post by **JohnD** » Sat Sep 23, 2006 5:50 pm

Thanks, lucky13, for that deeper explanation of 'How?', with some of 'Why?', which as usual depends on human error. Reassuring really, as I'm not a conspiracist.

I'll try the 'double-click' method next time I'm trapped.

John

BMAONE23 · Post by **BMAONE23** » Sat Sep 23, 2006 7:02 pm

John,
I just tried the "Double Click" method with no results. (maybe I didn't click fast enough though because a "Tripple Click" worked)

JohnD · Post by **JohnD** » Sat Sep 23, 2006 9:28 pm

Me too!
Three clicks!
"Any sufficiently advanced tecnology..........."

John