systemId (W3C DOM Core property)

Version Depr. Static Read-only
DOM1 No No Yes
Browser support (more…)
IE5.5+ FF1.5+ SA3+ OP9+
Partial Full Full Full


var sysid = document.doctype.systemId;

The example above saves a reference to the systemId of the doctype. So if we were on a page with an XHTML 1.0 Strict doctype, the sysid variable would have the value


The system identifier of a Notation, or null if no system identifier is specified.

This property is read-only.


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
Partial Partial Partial Full Full Full None None Full Full Full

Only Opera in XHTML mode or XML and Internet Explorer in XML are able to retrieve the systemId of an Entity or Notation, because those are the only environments in which the root objects themselves are exposed (see Entity and Notation for details).

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