Millisecond Forums

I want participants to enter words that are associated with their conceptualization of the word "status" as separate entries, one after the other (max 20).  
They type in a word, hit the 'Enter' key, then enter another word, hit the 'Enter' key, so on and so forth...
I currently have a simple textbox asking them to enter one word (see script below). 
How do I create a task that will go an iterative process of (1) store the word entry/response and then (2) clear textbox for new entry/response? 
Thanks in advance!

<surveypage status_words>
/ questions = [1=status_words]
/ finishlabel = "Click here to continue"
/ showpagenumbers = false
/ showquestionnumbers = false
</surveypage>

<textbox status_words>
/ caption = "At the top of society are the people who are the best off and have high status. ~nAt the bottom are the people who are the worst off and have low status. ~nWhat traits or characteristics tell you whether someone has low or high status?"
/ fontstyle = ("Arial", -18, false, false, false, false, 5, 0)
/ textboxsize = (20,20)
/ position = (10%,15%)
/ required = true
</textbox>