How to write advanced triggers for your surveys

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Surveys

Expressions

In the publish settings of the survey you can write a logical expression that must evaluate to true for the survey to be shown.

Values to be evaluated can be either a Number, String or Boolean. A number may be floating point or integer. Arrays or objects containing these types is also supported. The properties of an object can be accessed using the dot operator, and properties of an array by the in operator.

Values	Description
43, -1.234	Number
"hello"	String
true, false	Boolean
" \" \\ "	Escaping of double-quotes and blackslash in string
foo, a.b.c, 'foo-bar'	External data, se next section

Note! Strings must be double-quoted! Single quotes are for external variables.

Numeric arithmetic	Description
x + y	Add
x - y	Subtract
x * y	Multiply
x / y	Divide
x ^ y	Power
x mod y	Modulo

Note! Modulo always returns a positive number: -1 mod 3 == 2.

Comparisons	Description
x == y	Equals
x != y	Does not equal
x < y	Less than
x <= y	Less than or equal to
x > y	Greater than
x >= y	Greater than or equal to
x == y <= z	Chained relation, equivalent to (x == y and y <= z)
x ~= y	Regular expression match
x in (a, b, c)	Equivalent to (x == a or x == b or x == c)
x not in (a, b, c)	Equivalent to (x != a and x != b and x != c)

Boolean logic	Description
x or y	Boolean or
x and y	Boolean and
not x	Boolean not
if x then y else z	If boolean x is true, return value y, else return z
( x )	Explicity operator precedence

Objects and arrays	Description
(a, b, c)	Array
a in b	Array a is a subset of array b
x of y	Property x of object y

Functions	Description
abs(x)	Absolute value
ceil(x)	Round floating point up
empty(x)	True if x is undefined, null, an empty array or an empty string
exists(x)	True unless x is undefined or null
floor(x)	Round floating point down
log(x)	Natural logarithm
log2(x)	Logarithm base two
log10(x)	Logarithm base ten
max(a, b, c...)	Max value (variable length of args)
min(a, b, c...)	Min value (variable length of args)
round(x)	Round floating point
sqrt(x)	Square root

External data

The external data available at the time of evaluation. The best way to examine what data is available is using the javascript console on the website where the script is running. To examine the variable named data you need to run extellio.getData().

Name	Description
window	The global window object in the browser. This contains global variables, browser information etc.
distribution	Information about the survey that is being evaluated.
data	All surveys and websites related to Extellio and the current script being used.

Examples

Triggered when survey is in the same language code as the browser language.

window.navigator.language == distribution.surveyLanguage

Triggered when my global variable loggedIn is true and the device type is DESKTOP

window.loggedIn and "DESKTOP" in distribution.deviceTypes

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