A property can have attributes with which it is associated. These "property parameters" contain meta-information about the property or the property value. Property parameters are provided to specify such information as the location of an alternate text representation for a property value, the language of a text property value, the value type of the property value, and other attributes.
Property parameter values that contain the COLON, SEMICOLON, or COMMA character separators MUST be specified as quoted-string text values. Property parameter values MUST NOT contain the DQUOTE character. The DQUOTE character is used as a delimiter for parameter values that contain restricted characters or URI text. For example:
DESCRIPTION;ALTREP="cid:part1.0001@example.org":The Fall'98 Wild Wizards Conference - - Las Vegas\, NV\, USA
Property parameter values that are not in quoted-strings are case- insensitive.
The general property parameters defined by this memo are defined by the following notation:
icalparameter = altrepparam ; Alternate text representation / cnparam ; Common name / cutypeparam ; Calendar user type / delfromparam ; Delegator / deltoparam ; Delegatee / dirparam ; Directory entry / encodingparam ; Inline encoding / fmttypeparam ; Format type / fbtypeparam ; Free/busy time type / languageparam ; Language for text / memberparam ; Group or list membership / partstatparam ; Participation status / rangeparam ; Recurrence identifier range / trigrelparam ; Alarm trigger relationship / reltypeparam ; Relationship type / roleparam ; Participation role / rsvpparam ; RSVP expectation / sentbyparam ; Sent by / tzidparam ; Reference to time zone object / valuetypeparam ; Property value data type / other-param
other-param = (iana-param / x-param)
iana-param = iana-token "=" param-value *("," param-value)
; Some other IANA-registered iCalendar parameter.
x-param = x-name "=" param-value *("," param-value)
; A non-standard, experimental parameter.
Applications MUST ignore x-param and iana-param values they don't recognize.