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document.getElementById

Returns a reference to the element by its ID; the ID is a string which can be used to identify the element; it can be established using the id attribute in HTML, or from script.

Syntax

element = document.getElementById(id);

Parameters

id: is a case-sensitive string representing the unique ID of the element being sought.

Return Value

element: is a reference to an Element object, or null if an element with the specified ID is not in the document.

Example

HTML Content

<html>
<head>
  <title>getElementById example</title>
</head>
<body>
  <p id="para">Some text here</p>
  <button onclick="changeColor('blue');">blue</button>
  <button onclick="changeColor('red');">red</button>
</body>
</html>

JavaScript Content

function changeColor(newColor) {
  var elem = document.getElementById('para');
  elem.style.color = newColor;
}

Result

Notes

New users should note that the capitalization of 'Id' in the name of this method must be correct for the code to function; "getElementByID" does not work, however natural it may seem.

Unlike some other similar methods, getElementById is only available as a method of the global document object, and not available as a method on all element objects in the DOM. Because ID values must be unique throughout the entire document, there is no need for "local" versions of the function.

Example

<!doctype html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
    <div id="parent-id">
        <p>hello word1</p>
        <p id="test1">hello word2</p>
        <p >hello word3</p>
        <p>hello word4</p>
    </div>
    <script>
        var parentDOM = document.getElementById('parent-id');
        var test1=parentDOM.getElementById('test1');
        //throw error
        //Uncaught TypeError: parentDOM.getElementById is not a function
    </script>
</body>
</html>

If there is no element with the given id, this function returns null. Note that the id parameter is case-sensitive, so document.getElementById("Main") will return null instead of the element <div id="main"> because "M" and "m" are different for the purposes of this method.

Elements not in the document are not searched by getElementById(). When creating an element and assigning it an ID, you have to insert the element into the document tree with Node.insertBefore() or a similar method before you can access it with getElementById():

var element = document.createElement('div');
element.id = 'testqq';
var el = document.getElementById('testqq'); // el will be null!

Non-HTML documents. The DOM implementation must have information that says which attributes are of type ID. Attributes with the name "id" are not of type ID unless so defined in the document's DTD. The id attribute is defined to be of ID type in the common cases of XHTML, XUL, and other. Implementations that do not know whether attributes are of type ID or not are expected to return null.

Specification

Specification	Status	Comment
Document Object Model (DOM) Level 1 Specification The definition of 'getElementById' in that specification.	Recommendation	Initial definition for the interface
Document Object Model (DOM) Level 2 Core Specification The definition of 'getElementById' in that specification.	Recommendation	Supersede DOM 1
Document Object Model (DOM) Level 3 Core Specification The definition of 'getElementById' in that specification.	Recommendation	Supersede DOM 2
DOM The definition of 'getElementById' in that specification.	Living Standard	Intend to supersede DOM 3

Browser compatibility

Feature	Chrome	Edge	Firefox (Gecko)	Internet Explorer	Opera	Safari (WebKit)
Basic support	1.0	(Yes)	1.0 (1.7 or earlier)	5.5	7.0	1.0

Feature	Android	Edge	Firefox Mobile (Gecko)	IE Phone	Opera Mobile	Safari Mobile
Basic support	1.0	(Yes)	1.0 (1.0)	6.0	6.0	1.0

document.getElementById

Syntax

Parameters

Return Value

Example

HTML Content

JavaScript Content

Result

Notes

Example

Specification

Browser compatibility

See also