Autofill API (Beta)

Note
Optimizely Forms is only supported by MVC-based websites and HTML5-compliant browsers.
This is a Beta feature, which means that it is still in development.
In `Forms.Core`, `DataElementBlockBase` uses `Autofill` to prefill an element with a value from an external system.
`AutofillService` finds `AutofillProvider` based on the `MappingTable` as input, and gets suggestions from them. For example: if `formElement` is set to Email, `AutofillProvider` checks the CRM system, and selects Email data from the `ContactTables` and returns a suggestion.
Note
Render **\<datalist>** as suggestions for a visitor that views a form in View mode.
An element rendered in View mode can have a pre-selected value that is determined by the following input (by priority):
**Manual input from a user**
When a visitor selects a value, it is retained in the element.
**External system autofill**
If a form is connected to an Marketing Automation (MA) system, the MA system can provide information about the visitor to prefill into the element value as the selected value. The first suggestion is set automatically in the input as a predefined value.
**Predefined value**
An editor sets it in edit view.
[block:image]
{
  "images": [
    {
      "image": [  
        "https://files.readme.io/b9b1674-forms-external-mapping-3.png",  
        "forms-external-mapping-3.png",  
        691  
      ],
      "align": "left",
      "border": true
    }
  ]
}
[/block]
**In the demo project**
[DemoSystem](🔗﻿) acts like both `IExternalSystem` and `IAutofillProvider`.