Fieldtypes are modules that define a data type and field used to hold content for pages.
Every field used in your site has a defined type that originates from a Fieldtype module.
This section only covers a few fieldtypes where additional documentation is helpful.
The Comments Fieldtype enables the use of simple comments on any page in your site.
Using an manipulating image fieldtypes in ProcessWire. This page includes a few links to helpful threads in the forum having to do with usage of image fieldtypes.
The repeater fieldtype enables you to create a group of fields and make it repeatable in any quantity on your page. This opens many new possibilities with how you might manage and structure data.
Google Maps (Map Marker)
This Fieldtype holds an address or location name, and automatically geocodes the address to latitude/longitude using Google Maps API. This Fieldtype was also created to serve as an example of creating a custom Fieldtype and Inputfield that contains multiple pieces of data.
Validation: Fieldtypes vs. Inputfields
Overview of the way that Fieldtypes and Inputfields interact with each other when it comes to validation.
The Textarea Fieldtype is designed to hold any amount of text. Typically Textarea is used for multi-line text values.