prefix (W3C DOM Core property)

Version Depr. Static Read-only
DOM2 No No No
Browser support (more…)
IE5.5+ FF1.5+ SA3+ OP9+
Full Full Full Full


<html xmlns="" lang="en" xml:lang="en">

The example above shows the root element of an XHTML document. Its final attribute has the nodeName xml:lang, and therefore its prefix is xml.


The namespace prefix of this node; or null if this node has no namespace.

Only namespaced elements and attributes have a prefix; for other nodes, or for elements or attributes created with a non-namespace-aware method such as createElement, the prefix property is null.

Changing this value may also change the nodeName of this node (since the node name of a namespaced node is a combination of of localName and prefix), as well as the tagName and name properties of elements and attributes (respectively).

Changing the prefix of an element or attribute that has a default value in this document type does not cause a new default node to be created (ie. the prefix change might mean that the default is no longer present, but a new default will not appear to replace it).

This property is read/write.


Internet Explorer Firefox Safari Opera
5.5 6.0 7.0 1.5 2.0 3.0 1.3 2.0 3.0 9.0 9.5
Full Full Full Full Full Full Buggy Buggy Full Full Full

In Safari 1.3 and 2 the prefix always returns null.

: Behavior in HTML

Since prefix is an XML construct, it's only reasonable to judge its behavior in terms of XML (either on HTML pages in XHTML mode1, or pure XML). The behavioral variations of browsers in HTML mode2 are documented here for interest and reference, but the support summary table above does not consider this behavior (ie. if the property is fully supported in XML then it's considered to be fully supported, with no notes).

Internet Explorer does not implement this property in HTML, and will return undefined.


1 On XHTML pages served as application/xhtml+xml.

2 On XHTML or HTML pages served as text/html.

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