19. Dynamic Operations

Introduction

Dynamic Operations is a very powerful feature that allows you write custom JavaScript be included in a question in your TaroWorks form.

You can write custom JavaScript to run as either a calculation or a validation:

1. Calculations will pre-populate a response to the question on the form, e.g. automatically display a single select value or automatically set a date value to Today's date. The calculation is run when the page is loaded.
2. Validations will validate the response to a question that is entered by the mobile user, e.g. validate that a phone number only contains digits. An error will be thrown if the response entered does not meet the validation rule set preventing the user from proceeding to the next page.
   The validation will run when a user attempts to proceed from a page. Validations only run when there is an answer/response to run on and must therefore be stored on a question that is required.

Validation vs Calculation

	Validation	Calculation
Action	Display custom error message	Automatically generates responses to questions
Use of other responses	Yes	Yes
Response editable	Yes	No
Execution	User clicks next/leaves page	Page is loaded

• A. How do Dynamic Operations work?    

• B. How to add a Calculation Operation to a form question

  • Calculation Operation Examples

• C. How to add a Validation Operation to a form question

  • Validation Operation Examples
    

    • Regex Validation Examples

  • Combining Validation and Calculation

A. How do Dynamic Operations work?

You can configure a Dynamic Operation on any form question type except Static Content and End of Form. When you save the JavaScript in your question, the system will confirm that the code is valid JavaScript.

The syntax to refer to a question in a regular section is: 

tw.sectionname.questionname.value

The syntax to refer to a question in a repeat section is:

tw.repeatsectionname.current.questionname.value

or

tw.repeatsectionname[i].questionname.value

 where i represents the iterations of the repeat section starting from 0.

Starting TaroWorks 6.5, you have the option to test the JavaScript code snippet and ability to validate that all the references on the JavaScript code exist.

Starting TaroWorks 7.4, you have the option to determine whether Dynamic Operations should be run or not when the question is hidden via the “Run Hidden Dynamic Operations” checkbox. 

Functions

Function	Description
tw.sectionname.questionname.value	Returns the value of the response to a question
string.length tw.repeatsectionname.length	Returns the length of the response Returns number of repeats in a section
new Date()	Returns today’s date
tw.sectionname.questionname.isNaN	Checks whether response is not a number
tw.sectionname.questionname.hasAnswer	Checks whether a question has a response. This function cannot run on local variables, the syntax to the left is required. It also can't run on an optional question.

Operators

Operator	Description	Operator	Description
==	Equal to	&&	And
!=	Not Equal to	||	Or
>	Greater than	!	Not
>=	Greater than or Equal to	+	Add
<	Less than	-	Subtract
<=	Less than or Equal to	*	Multiply
		/	Divide

Methods

JavaScript Method	All in one Example
Array functions	var cars = ["Saab", "Volvo", "BMW"]; var total = "Array : " +cars.toString(); total = total + "Boolean " + Boolean(10 > 9); total = total + "Gloabl " + isNaN(123); var myObj = { "name":"John", "age":31, "city":"New York" }; var myJSON = JSON.stringify(myObj); total = total + "JSON " + myJSON;
Math
Date
Boolean
Global
JSON
Number

B. How to Add a Calculation Operation to a Form question

1. Click on the Forms Tab.
2. Create or Edit a Form.
3. Create or Edit a Question.
4. Check Add Dynamic Operations Using JavaScript. 
5. Select Calculation for your Operation. 
   
   
6. Enter your custom JavaScript or copy and paste from the code below.

   tw.register.registration_date.value= new Date();

7. Click Save.
   
   Response on Mobile
   
   

C. How to Add a Validation Operation to a Form question

1. Click on the Forms Tab.
2. Create or Edit a Form.
3. Create or Edit a Question.
4. Check Add Dynamic Operations Using JavaScript. 
5. Select Validation for your Operation. 
   
   
6. Enter your custom JavaScript or copy and paste from the code below.

   if (isNaN(tw.register.valid_phone_number.value))
   {
   throw "Phone Number should consist of only digits";
   }
   
   if (tw.register.valid_phone_number.value.length !== 10)
   {
   throw "Phone Number should be 10 numbers long";
   }

7. Click Save.
   
   Response on Mobile