这个JavaScript的正则表达式替换空白吗？

Question

我正在浏览twitter bootstrap的代码，并且我几次都在昏迷这段代码。

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

正则表达式是我的盲点，我找不出它们中的大多数。什么是替代？ ＃之后是否有空格？

附注。任何人都可以推荐正则表达式学费的好来源？

Answer 1

这里就是它的寻找：

.*  # 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，举例来说，它匹配的哈希标签之前会发生什么：

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