# What is %5C and why does Firefox like it so much?

**URL:** <https://boards.straightdope.com/t/what-is-5c-and-why-does-firefox-like-it-so-much/270070>\
**Category:** Factual Questions\
**Created:** [October 19, 2004, 5:54pm UTC](https://boards.straightdope.com/t/what-is-5c-and-why-does-firefox-like-it-so-much/270070 "2004-10-19T17:54:37Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Tabby\_Cat](https://avatars.discourse-cdn.com/v4/letter/t/6a8cbe/32.png) [@Tabby\_Cat](https://boards.straightdope.com/u/Tabby_Cat)\
**Post date:** [October 19, 2004, 5:54pm UTC](https://boards.straightdope.com/t/what-is-5c-and-why-does-firefox-like-it-so-much/270070/1 "2004-10-19T17:54:37Z")

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I’m working on a school website, and I put in some images in it. Opens fine in IE, which the school uses: Brilliant. But when I get home, the pictures are mysteriously gone!

Horrified, I check to see that the images are still there, and that the links didn’t get malformed somehow: bingo. %5C everywhere.

Mystified, I looked at the source code, only to realise that there’s no %5C in sight. So I opened it in IE, and bingo, everything’s as it should be.

Does anyone know what went wrong with Firefox? If it’s of any interest, the website is at [Page not found](http://societies.lse.ac.uk/lsego/) and yes, I know it sucks. 😃

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**Author:** ![Improv\_Geek](https://avatars.discourse-cdn.com/v4/letter/i/b3f665/32.png) [@Improv\_Geek](https://boards.straightdope.com/u/Improv_Geek)\
**Post date:** [October 19, 2004, 6:01pm UTC](https://boards.straightdope.com/t/what-is-5c-and-why-does-firefox-like-it-so-much/270070/2 "2004-10-19T18:01:13Z")

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%5c is one of the arcane symbols used to represent certain characters on servers. IE automatically converts it but Firefox takes it literally. %5c is the backslash (). To fix it for Firefox, make sure you use / (forward slash) instead. While Windows machines use \ to delineate folders, web standards use / to delineate folders (as does linux).

Hope this helps.

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**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\
**Post date:** [October 19, 2004, 6:15pm UTC](https://boards.straightdope.com/t/what-is-5c-and-why-does-firefox-like-it-so-much/270070/3 "2004-10-19T18:15:43Z")

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Yes, there are several places where the \ is used instead of the /, for example:

```auto

<IMG SRC=".\imgs\BarHighlights.gif">

```

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**Author:** ![ticker](https://avatars.discourse-cdn.com/v4/letter/t/d07c76/32.png) [@ticker](https://boards.straightdope.com/u/ticker)\
**Post date:** [October 19, 2004, 6:18pm UTC](https://boards.straightdope.com/t/what-is-5c-and-why-does-firefox-like-it-so-much/270070/4 "2004-10-19T18:18:11Z")

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**ronincyberpunk** beat me to the factual answer, so I will just add that, IMHO, the rather stricter behaviour of Firefox is to be preferred. If each browser tries too hard to accomodate small errors in HTML, the result is a web full of dodgy code which only works on a subset of browsers. Microsoft has never had a problem with being non-standard however.

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**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\
**Post date:** [October 20, 2004, 2:27am UTC](https://boards.straightdope.com/t/what-is-5c-and-why-does-firefox-like-it-so-much/270070/5 "2004-10-20T02:27:41Z")

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In the future, you might also try running your pages thru a validator ([like this one](http://validator.w3.org/)) which will show you items that do not meet official web standards. It is free, and only takes a few minutes.\*

But doing so will produce much more professional-quality webpages. This ought to be important in a school envoronment, where you are _learning_.

- It shows 43 errors remaining in that webpage.