Asynchronous JavaScript and XML (Ajax) is a technique used on the client-side to create asynchronous Web applications. With Ajax, the end-user experience is greatly improved because we are able to exchange data with the server without interfering with the display and behavior of the page. This is accomplished by sending small asynchronous requests to the server while the user interacts with the Web screen.

This allows for the end-user to update parts of the Web screen and not to have to wait for the response, while keeping the state of the page.


Think of filling a form with validations. With Ajax, validations of inputs are asynchronously requested to the server as the end-user fills them in. Once there's a response, it is rendered next to the corresponding field while the user goes on filling.

This delivers a better experience to end-users, with validations as they go and no waiting time for those validations.

In OutSystems Platform, there is a set of built-in tools that allow you to quickly implement Ajax techniques to improve the end-user experience in each situation.

Refresh Parts of the Web Screen

To refresh a widgets that are part of the Web Screen, simply give a name to those widgets and use the Ajax Refresh tool to in screens actions.  

In those actions change their Method property to Ajax Submit.

Learn more About the Ajax Refresh Tool.

Widgets with Ajax Capabilities

There are some widgets in Service Studio that have built-in Ajax capabilities.

In these widgets, you may set a screen action that is executed as an Ajax request when an event occurs in the widget.

Learn more about Widgets with Ajax Capabilities.

System Actions with Ajax Capabilities

There are some System actions in Service Studio that have built-in Ajax capabilities.  

They allow you manipulate a single row in list widgets without having to refresh the whole list.

Learn more about System Actions with Ajax Capabilities.

When to Use this API

Check the How to Design Screens with Ajax sample at OutSystems Forge.

See Also

Widgets with Ajax Capabilities | System Actions with Ajax Capabilities