Document: querySelector() method
The Document
method querySelector()
returns the first Element
within the document that matches the specified
selector, or group of selectors. If no matches are found, null
is returned.
Note: The matching is done using depth-first pre-order traversal of the document's nodes starting with the first element in the document's markup and iterating through sequential nodes by order of the number of child nodes.
Syntax
js
querySelector(selectors)
Parameters
selectors
-
A string containing one or more selectors to match. This string must be a valid CSS selector string; if it isn't, a
SyntaxError
exception is thrown. See Locating DOM elements using selectors for more about selectors and how to manage them.
Note: Characters that are not part of standard CSS syntax must be escaped using a backslash character. Since JavaScript also uses backslash escaping, be especially careful when writing string literals using these characters. See Escaping special characters for more information.
Return value
An Element
object representing the first element in the document
that matches the specified set of CSS selectors, or null
is returned if there are no matches.
If you need a list of all elements matching the specified selectors, you should use
querySelectorAll()
instead.
Exceptions
SyntaxError
DOMException
-
Thrown if the syntax of the specified selectors is invalid.
Usage notes
If the specified selector matches an ID that is incorrectly used more than once in the document, the first element with that ID is returned.
CSS pseudo-elements will never return any elements, as specified in the Selectors API.
Escaping special characters
To match against an ID or selectors that do not follow standard CSS syntax (by using a
colon or space inappropriately, for example), you must escape the character with a
backslash ("\
"). As the backslash is also an escape character in
JavaScript, if you are entering a literal string, you must escape it twice
(once for the JavaScript string, and another time for querySelector()
):
html
<div id="foo\bar"></div>
<div id="foo:bar"></div>
<script>
console.log("#foo\bar"); // "#fooar" (\b is the backspace control character)
document.querySelector("#foo\bar"); // Does not match anything
console.log("#foo\\bar"); // "#foo\bar"
console.log("#foo\\\\bar"); // "#foo\\bar"
document.querySelector("#foo\\\\bar"); // Match the first div
document.querySelector("#foo:bar"); // Does not match anything
document.querySelector("#foo\\:bar"); // Match the second div
</script>
Examples
Finding the first element matching a class
In this example, the first element in the document with the class
"myclass
" is returned:
js
const el = document.querySelector(".myclass");
Complex selectors
Selectors can also be really powerful, as demonstrated in the following example. Here,
the first <input>
element with the name "login"
(<input name="login"/>
) located inside a <div>
whose
class is "user-panel main" (<div class="user-panel main">
) in the
document is returned:
js
const el = document.querySelector("div.user-panel.main input[name='login']");
Negation
As all CSS selector strings are valid, you can also negate selectors:
js
const el = document.querySelector(
"div.user-panel:not(.main) input[name='login']"
);
This will select an input with a parent div with the user-panel
class but
not the main
class.
Specifications
Specification |
---|
DOM Standard # ref-for-dom-parentnode-queryselector① |
Browser compatibility
BCD tables only load in the browser