regex start and end matching

问题

So I'm having a little regex trouble, I have an expression that matches the starting with and the ending with separately. The problem occurs when I try to match the starting with and ending with both in the same expression and I don't understand why that would be a problem. I've even tried accounting for the content between the start and end tags, still no luck.

Works: /^([ ])?\[(\/?)gaiarch(=[^"]*)?]([ ])?/ig
Works: /([ ])?\[(\/?)gaiarch(=[^"]*)?]([ ])?$/ig
Doesn't work: /^([ ])?\[(\/?)gaiarch(=[^"]*)?]([ ])?$/ig

What I'm trying to have it match:

[gaiarch=slider]
[img url="http://i1251.photobucket.com/albums/hh543/Knight-Yoshi/trade_c.png" text="Trading Image" goto="http://www.gaiaonline.com/gaia/bank.php?mode=trade&uid=15388423"],[img url="http://i1251.photobucket.com/albums/hh543/Knight-Yoshi/friend_c.png" text="Friends Image" goto="http://www.gaiaonline.com/friends/add/15388423"][/gaiarch]

 [gaiarch=slider][img url="http://i1251.photobucket.com/albums/hh543/Knight-Yoshi/gaiaonline/thread/post/dark-center_bottom_zps419960f4.gif" text="bottom bar"]
[img url="http://i1251.photobucket.com/albums/hh543/Knight-Yoshi/gaiaonline/thread/post/star-say_right_zpsdc3769f3.png" goto="http://www.gaiaonline.com/"][/gaiarch] 

回答1:

The problem is that you're not matching what's in between the opening and closing tags; the expression expects either an opening or closing tag to be the only contents of your string.

To match whatever is between the opening and closing tag you need something like this:

/\[gaiarch(?:=([^\]]+))?\](.*?)\[\/gaiarch\]/ig

For this expression to work you can use RegExp.exec():

var re = /\[gaiarch(?:=([^\]]+))?\](.*?)\[\/gaiarch\]/ig;
while ((match = re.exec(str)) !== null) {
    console.log(match[1]) // "slider"
    console.log(match[2]) // "[img url=...]"
}

来源：https://stackoverflow.com/questions/18202328/regex-start-and-end-matching