Document.querySelector()

Returns the first element within the document (using depth-first pre-order traversal of the document's nodes|by first element in document markup and iterating through sequential nodes by order of amount of child nodes) that matches the specified group of selectors.

SyntaxEdit

element = document.querySelector(selectors);

where

• element is an element object.
• selectors is a string containing one or more CSS selectors separated by commas.

ExampleEdit

In this example, the first element in the document with the class "myclass" is returned:

var el = document.querySelector(".myclass");

Example: PowerfulEdit

Selectors can also be really powerful as demonstrated in the following example. Here, the first element <input name="login"/> within a <div class="user-panel main"> in the document is returned:

var el = document.querySelector("div.user-panel.main input[name=login]");

NotesEdit

Returns null if no matches are found; otherwise, it returns the first matching element.

If the selector matches an ID and this ID is erroneously used several times in the document, it returns the first matching element.

Throws a SYNTAX_ERR exception if the specified group of selectors is invalid.

querySelector() was introduced in the Selectors API.

The string argument pass to querySelector must follow the CSS syntax.

CSS Pseudo-elements will never return any elements, as specified in the Selectors API

To match ID or selectors that do not follow the CSS syntax (by using a colon or space inappropriately for example), you must escape the character with a back slash. As the backslash is 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"
  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>

SpecificationsEdit

Browser compatibilityEdit

See alsoEdit

• element.querySelector()
• document.querySelectorAll()
• element.querySelectorAll()
• Code snippets for querySelector