iMacros supports 3 types of variables:
2. Built-in variables. They contain certain values set by iMacros e. g. !URLCURRENT or define certain iMacros properties e. g. !TIMEOUT_PAGE. A special subset are the !COLn variables that are used to read data from CSV files. These variables cannot be set with iimSet or -var_varname, they can only be used with the SET macro command.
3. User-defined variables. They are defined in-macro using the SET command. They can also be defined with iimSet in a script and are used to send values from a script to the macro. To get data from a macro to the calling script the iimGetLastExtract command and the !EXTRACT variable are used.