這個JavaScript的正則表達式替換空白嗎？

Question

我正在瀏覽twitter bootstrap的代碼，並且我幾次都在昏迷這段代碼。

href.replace(/.*(?=#[^\s]+$)/, '') //strip for ie7 

正則表達式是我的盲點，我找不出它們中的大多數。什麼是替代？ ＃之後是否有空格？

附註。任何人都可以推薦正則表達式學費的好來源？

Answer 1

這裏就是它的尋找：

.*  # any number of characters (optional) 
(?= # open a lookahead 
#  # find a hash tag 
[^\s]+ # at least one non-whitespace character 
$  # end of line 
)  # close the lookahead 

因此，舉例來說，它匹配的哈希標籤之前會發生什麼：

replace this!#foobar <-- matches: replace this! 
hello world#goodbye <-- matches: hello world 
no match here !  <-- doesn't match anything because there is no hash 
what?#     <-- does not match because there is nothing after the hash 
what?# asd    <-- does not match because there is a whitespace-character