With Gatedcontent.com it is possible using field rules to create fields that dynamically change based on user interactions. A great example of this is a smart dropdown. In this example, we will create two fields, when a option is selected in the first field it will narrow down the options of the second.
To get started create two picklist fields, one for Business Sector and one for Industry. In the image below you can see that the options and labels for business sector have been added.
In the Industry field all of the possible options have been added, this means this list is very long and could create a frustrating user experience.
To make the process easier for the user we will add some field rules to Industry that will narrow the selection depending on the Business Sector selected previously. Below is an example of rule that states:
Continuously monitor the gate, IF the user selects Education in the Business Sector field THEN change the picklist options to; Higher Education, Library Education, Primary Education. 
Repeat this step for each Business Sector value.
To make the Industry field appear when the user makes a selection in Business Sector add a final rule that states:
Continuously monitor this field, IF the Business Sector field is not empty THEN show this field, OTHERWISE hide this field.
Push the changes live, create or select a form type which contains both Industry and Business Sector fields and a gate with this form type selected.
At first only the Business Sector field will display because of the final show/hide rule we added.
When Education is selected the Industry field will appear displaying the specific options we input in the rules.
Likewise for the other Business Sector options.
Important note: When using progressive form type behaviour ensure that both fields are displayed on the same step otherwise it can create a confusing customer experience when on the next session they only see reduced Industry options.
Got questions about smart dropdowns? Email us at support@gatedcontent.com or click +New Support Ticket above.