javascript - Why does this non-capturing group capture? -

javascript - Why does this non-capturing group capture? -

applying regex pattern:

/(?:(^| |\>|\+))+([a-z\-\_]+)/gi

to string:

body.test ol+li ol > li #foobar p>span a[href=*]

i these matches, comma separated:

body, ol,+li, ol, > li, p,>span,

why matches have leading space , > , + sign? i'd expect part of regex (?:(^| |\>|\+)) match signs, not capture them.

edit: trying match html tags , css selectors contributing css specificity of css selector. want match each li or span or forth on own, without + or >.

capturing not same matching. since you're specifying combinators in pattern, picked matcher, regardless of whether they're captured or non-captured.

to capture, need exec() regular look on string , loop through results, will contain capture groups. i've cleaned pattern , modified doesn't capture unnecessarily , recognize the general sibling combinator ~:

var sel = "body.test ol+li ol > li #foobar p>span a[href=*]"; var re = /(?:^| |>|\+|~)+([a-z_-]+)/gi; var matches = [], m; while (m = re.exec(sel)) { matches.push(m[1]); }

you obtain expected matches:

body, ol, li, ol, li, p, span,

javascript regex css-selectors pattern-matching