If you are using Forms 1.0:
- set the field type to Select
- click Apply Change to force a browser refresh
- check the box Allow Multiple Selection
- enter the value list, the first element beig Please Selct or another dummy value.
The end result of Forms 1.0 and 2.0 is the same: the values are sent to the lead database as Valie1; Value2
A smart list would have "Contains" instead of "Is".
Form fill out
Standard multi select: Cmd-Click (Mac) or Ctrl-Click (Windows)
Form results
Lead database
In forms 1.0