-
Templates
-
Simple Questions
-
Text Entry
-
Date-Time Entry
-
Numeric Entry
-
Color Input
-
Radio Button Group
-
Dropdown
-
Dropdown: Load Data from Web Services
-
Dropdown with Lazy Loading
-
Multi-Select Dropdown
-
Checkboxes
-
Carry Forward Responses
-
Image Picker
-
Yes/No Question
-
Signature
-
Multiple Textboxes
-
Rating Scale
-
Rating Scale UI Adaptation Modes
-
Ranking
-
Long Text
-
Image
-
HTML
-
File Upload
-
Expression
-
Expression (using async functions)
-
-
Matrix Table Questions
-
Panel & Dynamic Panel
-
Survey
-
Title and Logo
-
Questions in one line
-
Survey Options
-
Auto-Populate Form Fields
-
Merge Question Values
-
Edit saved survey
-
Read-only/display mode
-
Show Preview before complete
-
Pop-Up Survey
-
Context actions in element titles
-
Modify title tags
-
Custom render of survey elements
-
File - custom preview
-
File - delayed upload
-
Lazy questions rendering
-
-
Quizzes and Scored Surveys
-
Customize Rendering
-
Integration with Third-Party Libraries
-
Appearance customization
-
Navigation
-
Conditions and Triggers
-
Conditional Visibility
-
Simplify Cascade Conditions
-
Dynamic Default Question Values
-
Complex Questions in Expressions
-
Custom Functions in Expressions
-
Implement a Custom Expression Property
-
Dynamic Questions with Conditional Logic
-
Hide Question Elements (Rows, Columns, Choices)
-
Show/Hide individual items in radiogroup/checkbox/dropdown
-
Hide Rows and Columns in a Matrix Table
-
Hide Rows and Columns in a Matrix Dropdown Question
-
Conditional Logic to Enable or Disable Questions
-
Complete Trigger
-
CopyValue Trigger
-
SetValue Trigger
-
Run Expression Trigger
-
-
Text Formatting
-
Survey Localization
-
Input Validation
-
SurveyJS Storage
Server-Side Form Validation Using an Event
This example demonstrates how you can handle an event to process user input on the server side. SurveyJS also allows you to build an validation expression for the same purpose. This article explains the difference between server-side input validation using expressions and an event handler. Select React, Vue, Knockout, jQuery, or Angular to view an example for your JavaScript framework of choice.
Event Handler vs Expressions
Event Handler
You can validate user input in the onServerValidateQuestions
event handler. Survey authors have no access to this handler and therefore cannot disable custom validation. The event handler is executed on navigation to the next page and on survey completion. This behavior does not allow for immediate validation.
Expressions
If you want to query the server from an expression, implement and register a custom validator in your JavaScript code. Survey authors cannot modify the validator, but they can decide whether or not to use it in their expressions when they design their surveys. Immediate validation is available. Refer to the following demo for more information: Server-Side Form Validation Using Expressions.
Handle the onServerValidateQuestions
Event
An onServerValidateQuestions
event handler accepts the survey as the first argument and an object with the following fields as the second argument:
data
- An object that contains question values.errors
- An object for your error messages. Set error messages as follows:errors["questionName"] = "My error message"
;complete()
- A method that you should call when the request to the server has completed.
In this server-side validation example, you should enter a country name into the form field. A callback assigned to the onServerValidateQuestions
event handler will fetch a list of countries and check whether the entered country is in it. If the country is not found, the form field will display a validation error.
-
Templates
-
Simple Questions
-
Text Entry
-
Date-Time Entry
-
Numeric Entry
-
Color Input
-
Radio Button Group
-
Dropdown
-
Dropdown: Load Data from Web Services
-
Dropdown with Lazy Loading
-
Multi-Select Dropdown
-
Checkboxes
-
Carry Forward Responses
-
Image Picker
-
Yes/No Question
-
Signature
-
Multiple Textboxes
-
Rating Scale
-
Rating Scale UI Adaptation Modes
-
Ranking
-
Long Text
-
Image
-
HTML
-
File Upload
-
Expression
-
Expression (using async functions)
-
-
Matrix Table Questions
-
Panel & Dynamic Panel
-
Survey
-
Title and Logo
-
Questions in one line
-
Survey Options
-
Auto-Populate Form Fields
-
Merge Question Values
-
Edit saved survey
-
Read-only/display mode
-
Show Preview before complete
-
Pop-Up Survey
-
Context actions in element titles
-
Modify title tags
-
Custom render of survey elements
-
File - custom preview
-
File - delayed upload
-
Lazy questions rendering
-
-
Quizzes and Scored Surveys
-
Customize Rendering
-
Integration with Third-Party Libraries
-
Appearance customization
-
Navigation
-
Conditions and Triggers
-
Conditional Visibility
-
Simplify Cascade Conditions
-
Dynamic Default Question Values
-
Complex Questions in Expressions
-
Custom Functions in Expressions
-
Implement a Custom Expression Property
-
Dynamic Questions with Conditional Logic
-
Hide Question Elements (Rows, Columns, Choices)
-
Show/Hide individual items in radiogroup/checkbox/dropdown
-
Hide Rows and Columns in a Matrix Table
-
Hide Rows and Columns in a Matrix Dropdown Question
-
Conditional Logic to Enable or Disable Questions
-
Complete Trigger
-
CopyValue Trigger
-
SetValue Trigger
-
Run Expression Trigger
-
-
Text Formatting
-
Survey Localization
-
Input Validation
-
SurveyJS Storage