You can select the dropdown menu like this.
This is the current script.
TAG POS=1 TYPE=SELECT FORM=ACTION:/es/crear-tu-blog/ ATTR=NAME:domain CONTENT=#5
In some cases, I saw %5
so I am not sure is it %
or #
before the number. The number 5, in this case, is just an example.
Here is what it says on iMacros.
http://wiki.imacros.net/TAG
Scroll down to where it says dropdown menu.
The next step is to create a random number with use of JavaScript. On the link below, you can get the functions for that purpose.
Generating random whole numbers in JavaScript in a specific range?
After you've mastered that the next step is to implement it in iMacros. You have to use JavaScript scripting.
var macro;
macro ="CODE:";
macro +="TAG POS=1 TYPE=SELECT FORM=ACTION:/es/crear-tu-blog/ ATTR=NAME:domain CONTENT=#{{number}}";
iimSet("number",some_random_number)
iimPlay(macro)