Provided by: libmojolicious-perl_9.35+dfsg-1_all 
NAME
Mojo::DOM::CSS - CSS selector engine
SYNOPSIS
use Mojo::DOM::CSS;
# Select elements from DOM tree
my $css = Mojo::DOM::CSS->new(tree => $tree);
my $elements = $css->select('h1, h2, h3');
DESCRIPTION
Mojo::DOM::CSS is the CSS selector engine used by Mojo::DOM, based on the HTML Living
Standard <https://html.spec.whatwg.org> and Selectors Level 3
<https://www.w3.org/TR/css3-selectors/>.
SELECTORS
All CSS selectors that make sense for a standalone parser are supported.
*
Any element.
my $all = $css->select('*');
E
An element of type "E".
my $title = $css->select('title');
E[foo]
An "E" element with a "foo" attribute.
my $links = $css->select('a[href]');
E[foo="bar"]
An "E" element whose "foo" attribute value is exactly equal to "bar".
my $case_sensitive = $css->select('input[type="hidden"]');
my $case_sensitive = $css->select('input[type=hidden]');
E[foo="bar" i]
An "E" element whose "foo" attribute value is exactly equal to any (ASCII-range) case-
permutation of "bar". Note that this selector is EXPERIMENTAL and might change without
warning!
my $case_insensitive = $css->select('input[type="hidden" i]');
my $case_insensitive = $css->select('input[type=hidden i]');
my $case_insensitive = $css->select('input[class~="foo" i]');
This selector is part of Selectors Level 4 <https://dev.w3.org/csswg/selectors-4>, which
is still a work in progress.
E[foo="bar" s]
An "E" element whose "foo" attribute value is exactly and case-sensitively equal to "bar".
Note that this selector is EXPERIMENTAL and might change without warning!
my $case_sensitive = $css->select('input[type="hidden" s]');
This selector is part of Selectors Level 4 <https://dev.w3.org/csswg/selectors-4>, which
is still a work in progress.
E[foo~="bar"]
An "E" element whose "foo" attribute value is a list of whitespace-separated values, one
of which is exactly equal to "bar".
my $foo = $css->select('input[class~="foo"]');
my $foo = $css->select('input[class~=foo]');
E[foo^="bar"]
An "E" element whose "foo" attribute value begins exactly with the string "bar".
my $begins_with = $css->select('input[name^="f"]');
my $begins_with = $css->select('input[name^=f]');
E[foo$="bar"]
An "E" element whose "foo" attribute value ends exactly with the string "bar".
my $ends_with = $css->select('input[name$="o"]');
my $ends_with = $css->select('input[name$=o]');
E[foo*="bar"]
An "E" element whose "foo" attribute value contains the substring "bar".
my $contains = $css->select('input[name*="fo"]');
my $contains = $css->select('input[name*=fo]');
E[foo|="en"]
An "E" element whose "foo" attribute has a hyphen-separated list of values beginning (from
the left) with "en".
my $english = $css->select('link[hreflang|=en]');
E:root
An "E" element, root of the document.
my $root = $css->select(':root');
E:nth-child(n)
An "E" element, the "n-th" child of its parent.
my $third = $css->select('div:nth-child(3)');
my $odd = $css->select('div:nth-child(odd)');
my $even = $css->select('div:nth-child(even)');
my $top3 = $css->select('div:nth-child(-n+3)');
E:nth-last-child(n)
An "E" element, the "n-th" child of its parent, counting from the last one.
my $third = $css->select('div:nth-last-child(3)');
my $odd = $css->select('div:nth-last-child(odd)');
my $even = $css->select('div:nth-last-child(even)');
my $bottom3 = $css->select('div:nth-last-child(-n+3)');
E:nth-of-type(n)
An "E" element, the "n-th" sibling of its type.
my $third = $css->select('div:nth-of-type(3)');
my $odd = $css->select('div:nth-of-type(odd)');
my $even = $css->select('div:nth-of-type(even)');
my $top3 = $css->select('div:nth-of-type(-n+3)');
E:nth-last-of-type(n)
An "E" element, the "n-th" sibling of its type, counting from the last one.
my $third = $css->select('div:nth-last-of-type(3)');
my $odd = $css->select('div:nth-last-of-type(odd)');
my $even = $css->select('div:nth-last-of-type(even)');
my $bottom3 = $css->select('div:nth-last-of-type(-n+3)');
E:first-child
An "E" element, first child of its parent.
my $first = $css->select('div p:first-child');
E:last-child
An "E" element, last child of its parent.
my $last = $css->select('div p:last-child');
E:first-of-type
An "E" element, first sibling of its type.
my $first = $css->select('div p:first-of-type');
E:last-of-type
An "E" element, last sibling of its type.
my $last = $css->select('div p:last-of-type');
E:only-child
An "E" element, only child of its parent.
my $lonely = $css->select('div p:only-child');
E:only-of-type
An "E" element, only sibling of its type.
my $lonely = $css->select('div p:only-of-type');
E:empty
An "E" element that has no children (including text nodes).
my $empty = $css->select(':empty');
E:any-link
Alias for "E:link". Note that this selector is EXPERIMENTAL and might change without
warning! This selector is part of Selectors Level 4
<https://dev.w3.org/csswg/selectors-4>, which is still a work in progress.
E:link
An "E" element being the source anchor of a hyperlink of which the target is not yet
visited (":link") or already visited (":visited"). Note that Mojo::DOM::CSS is not
stateful, therefore ":any-link", ":link" and ":visited" yield exactly the same results.
my $links = $css->select(':any-link');
my $links = $css->select(':link');
my $links = $css->select(':visited');
E:visited
Alias for "E:link".
E:scope
An "E" element being a designated reference element. Note that this selector is
EXPERIMENTAL and might change without warning!
my $scoped = $css->select('a:not(:scope > a)');
my $scoped = $css->select('div :scope p');
my $scoped = $css->select('~ p');
This selector is part of Selectors Level 4 <https://dev.w3.org/csswg/selectors-4>, which
is still a work in progress.
E:checked
A user interface element "E" which is checked (for instance a radio-button or checkbox).
my $input = $css->select(':checked');
E.warning
An "E" element whose class is "warning".
my $warning = $css->select('div.warning');
E#myid
An "E" element with "ID" equal to "myid".
my $foo = $css->select('div#foo');
E:not(s1, s2)
An "E" element that does not match either compound selector "s1" or compound selector
"s2". Note that support for compound selectors is EXPERIMENTAL and might change without
warning!
my $others = $css->select('div p:not(:first-child, :last-child)');
Support for compound selectors was added as part of Selectors Level 4
<https://dev.w3.org/csswg/selectors-4>, which is still a work in progress.
E:is(s1, s2)
An "E" element that matches compound selector "s1" and/or compound selector "s2". Note
that this selector is EXPERIMENTAL and might change without warning!
my $headers = $css->select(':is(section, article, aside, nav) h1');
This selector is part of Selectors Level 4 <https://dev.w3.org/csswg/selectors-4>, which
is still a work in progress.
E:has(rs1, rs2)
An "E" element, if either of the relative selectors "rs1" or "rs2", when evaluated with
"E" as the :scope elements, match an element. Note that this selector is EXPERIMENTAL and
might change without warning!
my $link = $css->select('a:has(> img)');
This selector is part of Selectors Level 4 <https://dev.w3.org/csswg/selectors-4>, which
is still a work in progress. Also be aware that this feature is currently marked
"at-risk", so there is a high chance that it will get removed completely.
E:text(string_or_regex)
An "E" element containing text content that substring matches "string_or_regex" case-
insensitively or that regex matches "string_or_regex". For regular expressions use the
format ":text(/.../)". Note that this selector is EXPERIMENTAL and might change without
warning!
# Substring match
my $login = $css->select(':text(Log in)');
# Regex match
my $login = $css->select(':text(/Log ?in/)');
# Regex match (case-insensitive)
my $login = $css->select(':text(/(?i:Log ?in)/)');
This is a custom selector for Mojo::DOM and not part of any spec.
A|E
An "E" element that belongs to the namespace alias "A" from CSS Namespaces Module Level 3
<https://www.w3.org/TR/css-namespaces-3/>. Key/value pairs passed to selector methods are
used to declare namespace aliases.
my $elem = $css->select('lq|elem', lq => 'http://example.com/q-markup');
Using an empty alias searches for an element that belongs to no namespace.
my $div = $c->select('|div');
E F
An "F" element descendant of an "E" element.
my $headlines = $css->select('div h1');
E > F
An "F" element child of an "E" element.
my $headlines = $css->select('html > body > div > h1');
E + F
An "F" element immediately preceded by an "E" element.
my $second = $css->select('h1 + h2');
E ~ F
An "F" element preceded by an "E" element.
my $second = $css->select('h1 ~ h2');
E, F, G
Elements of type "E", "F" and "G".
my $headlines = $css->select('h1, h2, h3');
E[foo=bar][bar=baz]
An "E" element whose attributes match all following attribute selectors.
my $links = $css->select('a[foo^=b][foo$=ar]');
ATTRIBUTES
Mojo::DOM::CSS implements the following attributes.
tree
my $tree = $css->tree;
$css = $css->tree(['root']);
Document Object Model. Note that this structure should only be used very carefully since
it is very dynamic.
METHODS
Mojo::DOM::CSS inherits all methods from Mojo::Base and implements the following new ones.
matches
my $bool = $css->matches('head > title');
my $bool = $css->matches('svg|line', svg => 'http://www.w3.org/2000/svg');
Check if first node in "tree" matches the CSS selector. Trailing key/value pairs can be
used to declare xml namespace aliases.
select
my $results = $css->select('head > title');
my $results = $css->select('svg|line', svg => 'http://www.w3.org/2000/svg');
Run CSS selector against "tree". Trailing key/value pairs can be used to declare xml
namespace aliases.
select_one
my $result = $css->select_one('head > title');
my $result =
$css->select_one('svg|line', svg => 'http://www.w3.org/2000/svg');
Run CSS selector against "tree" and stop as soon as the first node matched. Trailing
key/value pairs can be used to declare xml namespace aliases.
DEBUGGING
You can set the "MOJO_DOM_CSS_DEBUG" environment variable to get some advanced diagnostics
information printed to "STDERR".
MOJO_DOM_CSS_DEBUG=1
SEE ALSO
Mojolicious, Mojolicious::Guides, <https://mojolicious.org>.