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.
element = document.querySelector(selectors);
selectorsDOMString containing one or more selectors to match. This string must be a valid CSS selector string; if it isn't, a SYNTAX_ERR 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.
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.
SYNTAX_ERRselectors is invalid.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.
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()):
<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> In this example, the first element in the document with the class "myclass" is returned:
var el = document.querySelector(".myclass");
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:
var el = document.querySelector("div.user-panel.main input[name='login']");
| Specification | Status | Comment |
|---|---|---|
| Selectors API Level 2 The definition of 'document.querySelector()' in that specification. | Obsolete | |
| Selectors API Level 1 The definition of 'document.querySelector()' in that specification. | Obsolete | Initial definition |
| Desktop | ||||||
|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | |
| Basic support | 1 | Yes | 3.5 | 8 | 10 | 3.2 |
| Mobile | |||||||
|---|---|---|---|---|---|---|---|
| Android webview | Chrome for Android | Edge Mobile | Firefox for Android | Opera for Android | iOS Safari | Samsung Internet | |
| Basic support | Yes | Yes | Yes | Yes | 10 | 3.2 | ? |
Element.querySelector()Document.querySelectorAll()Element.querySelectorAll()
© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/document/querySelector