SP.Publishing.CustomizableString.usesDefaultValue property (sp.publishing)
Gets or sets whether the current value is the default value.
Applies to: apps for SharePoint | SharePoint Foundation 2013 | SharePoint Server 2013
var value = SP.Publishing.CustomizableString.get_usesDefaultValue()
SP.Publishing.CustomizableString.set_usesDefaultValue(value)
Return value
true if the current value is the default value; otherwise, false.