Functions allow executing dynamic content in a Scenario. Wherever a variable can be used, a function can be used too.

The standard syntax for functions is "${__myFunction(arg1, arg2)}" where arguments can be variables or functions. For example: "${__func1(${__func2(${myVar})})}".

For more information, see Use variables.

JavaScript Libraries

NeoLoad 7.1 is provided with a default library of functions accessible with a click in Edit > JS Libraries.


Each of these functions can be used in a NeoLoad project.

Functions description

The table below identifies all the functions provided by default when creating a new project in NeoLoad. For more details, in NeoLoad, go to Edit > JS Librairies.

Also, any custom function from any custom library can be used if declared in the NeoLoad JavaScript library. For more information, see JavaScript libraries.

Function name


__randomNumber(x, y)

Returns a random number that lies between the given min and max values.


Encodes an URL.


Decodes an URL.


Escapes the characters in a String using HTML entities.


Unescapes a string containing HTML entity escapes to a string containing the actual Unicode characters corresponding to the escapes.

__randomString(length, chars)

Returns a random String of length using characters in chars to use.


Returns the result of evaluating a list of numbers as Unicode characters.

__changeCase(s, mode)

Returns a string value which case has been changed following a specific mode.


Returns the sum of two or more integer values.


Returns the sum of two or more long values.


Returns the ID of the VU that is being executed.


Returns the name of the Virtual User Path name that is being executed.


Returns the local IP address.


Returns the local hostname.


Returns a pseudo random type 4 Universally Unique IDentifier (UUID).

__digest(algorithm, strToEncode, salt, upperCase)

Returns an encrypted value in the specific hash algorithm with the optional salt and upper case option.

Migration procedure

Below is the procedure to apply when working with NeoLoad projects prior to 7.1 version:

  1. In NeoLoad, create a new project. The default JavaScript library is created in the "Scripts" folder of the new project.
  2. Copy the library from the new project to paste it in the "scripts" folder of your existing project.
  3. Declare the library as described in Create a JavaScript library.