Suppose there is a dropdown with the field name 'Priority' and its label and values configured as 'Immediate', 'High' and 'Medium' respectively. You want its background color to change depending upon the selected value. In such a case, you can use the drag and drop code editor to define a condition like below upon the 'onChange' event:

Here are the steps to understand how you can define such a condition:

1. From the left panel, go to first option 'Logic'. It will populate a list of logical blocks. Select the first 'if' block and drag it to the center of the editor.

2. Click on the gear icon inside the 'if' block. It will populate options available for selected block.

3. Within the popup, drag and drop the 'else if' block just below the 'if' block as shown below.

4. Now, close the popup by clicking on the gear icon once again.

5. Go back to left panel and select 'Logic'. Select the second block and drag it to the center adjoining the 'if' block as shown below.

6. Go back to left panel and select 'Custom Functions'. Select the second block 'Get Value' and drag it to the center adjoining the first blank box opposite the 'if' block as shown below.
In the 'Select Control Name' dropdown, select 'Priority'.

7. Go back to left panel and select 'Text'. Select the first block and drag it to the center adjoining the second blank box opposite the 'if' block.
In the text box, enter the text 'Immediate'.

8. Go back to left panel and select 'Custom Functions'. Select the third block 'Setter' and drag it to the center adjoining the 'do' block as shown below.
In the 'Select Control Name' dropdown, select 'Priority'. Keep the 'Property Name' chosen as 'Background Color'. Click on the 'Value' box and in the color picker that opens, select red color.

9. Now select and copy the entire block opposite the 'if' block by pressing Ctrl+C, and paste it adjoining the 'else if' block as shown below. Replace the 'Immediate' text with 'High'.

10. Similarly, select and copy the entire block opposite the first 'do' block by pressing Ctrl+C, then paste it adjoining the second 'do' block as shown below. Replace the red color with yellow color in the 'Value' box this time.

11. Click on the gear icon in 'if' block. Within the popup, drag and drop a second 'else if' block just below the existing 'else if' block as shown below.

12. Now, close the popup by clicking on the gear icon once again.

13. Select and copy the entire block opposite the 'if' block by pressing Ctrl+C, and paste it adjoining the second 'else if' block as shown below. Replace the 'Immediate' text with 'Medium'.

14. Similarly, select and copy the entire block opposite the first 'do' block by pressing Ctrl+C, then paste it adjoining the third 'do' block as shown below. Replace the red color with green color in the 'Value' box this time.

15. Click on the gear icon in 'if' block. Within the popup, drag and drop an 'else' block just below the second 'else if' block as shown below.

16. Now, close the popup by clicking on the gear icon once again.

17. Select and copy the entire block opposite the first 'do' block by pressing Ctrl+C, then paste it adjoining the 'else' block as shown below. Replace the red color with white color in the 'Value' box this time.

18. Once done, click 'OK' (at bottom right) to save the changes and exit the code editor, then save / publish the form design as needed. Once the form design is published and executed, the changes will be applicable for the new forms created under the related form type.