SP.Taxonomy.TaxonomyField.isTermSetValid property (sp.taxonomy)
Gets a Boolean value that specifies whether the TermSet object identified by TaxonomyField.termSetId property exists and is available for tagging.
Applies to: apps for SharePoint | SharePoint Foundation 2013 | SharePoint Server 2013
var value = SP.Taxonomy.TaxonomyField.get_isTermSetValid()
Return value
true if the TermSet identified by the termSetId property exists and is available for tagging; otherwise, false.