試驗了一下python的urllib庫以及js 的 encodeURIComponent 均不會替換。空格encode也是替換成了 '%20' 。python提供了urllib.quote_plus, urlib.unquote_plus來處理空格->加号，看起來還是比較合理的。
查了一下 RFC 3986: 有下面一段
Scheme names consist of a sequence of characters beginning with a letter and followed by any combination of letters, digits, plus ("+"), period ("."), or hyphen ("-").
RFC 2396 有下面的一段
The plus "+", dollar "$", and comma "," characters have been added to those in the "reserved" set, since they are treated as reserved within the query component.
表示加号已經是url的保留字了，不需要轉義。
然後html4文檔裡才有關于加号的轉義：
application/x-www-form-urlencoded
Forms submitted with this content type must be encoded as follows:
Control names and values are escaped. Space characters are replaced by`+', and then reserved characters.....
聲明隻有content-type為application/x-www-form-urlencoded時才會對+做轉義。
又翻了下php的文檔，發現有一個
rawurlencode() - URL-encode according to RFC 3986
也就是php又搞了rawurlencode和rawurldecode把标準實作了。。。。
不能反一下麼，畢竟大部分人應該都會用urlencode。php真是蛋疼啊。。。。