Attr.specified

none

Thanks to this attribute you can find out something about "DTD-background" of tested attribute. In summary:

• If the attribute has an assigned value in the document then specified is true, and the value is the assigned value.
• If the attribute has no assigned value in the document and has a default value in the DTD, then specified is false, and the value is the default value in the DTD.
• If the attribute has no assigned value in the document and has a value of #IMPLIED in the DTD, then the attribute does not appear in the structure model of the document.
• If the ownerElement attribute is null (i.e. because it was just created or was set to null by the various removal and cloning operations) specified is true.

  var attr = document.createAttribute('temp');
  attr.value = 'temporary';
  var output = attr.specified;