Why is %2526 used instead of %26 to encode an &?
Im invoking a URL to an external site and when I encode the & as %2526 the parameters are passed correctly but when I just use %26 they are not.
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blue-sky
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That depends on how the external site does the decoding. `encodeURIComponent("&")` gives me `"%26"`. – Alexander Pavlov Feb 15 '12 at 11:58
5 Answers
23
If you url-encode an ampersand you get %26. If you url-encode %26 you get %2526. Thus, it is url-encoded twice.
Sjoerd
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%25 is the percent character, so %2526 URLDecoded results in
%26
which URLDecoded results in
&
For some reason, the call you make seems to require doubly percent encoded input. Without knowing more about what you're doing, it's impossible to know why, but I guess all is in order.
Pekka
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Just wondering - do you carry these codes in your head or did you run it throug a decoder? :) – Czechnology Feb 15 '12 at 11:59
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@Czechnology I ran them through a decoder. :) I couldn't memorize stuff like this to save my life! – Pekka Feb 15 '12 at 12:00
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Apparently it gets decoded twice in the process, first from %2526 to %26 and then from %26 to &.
You shouldn't dwell too long on the why; if this works, just use it like this.
Mr Lister
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If the URL is used in return URL or value of another query string, the Reserved and Excluded characters should be doubled encoded. & is single-encoded as %26 and double-encoded as %2526.
Ebad Masood
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& is indeed encoded as %26.
You can test it creating an HTML file, opening it in a browser, inputing symbols you need to test and looking at the resulting URL in browser:
<form>
<input type='text' name='qwe'>
<input type='submit'>
</form>
Oleg Mikheev
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