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Your LimeSurvey version: [3.28]
Own server or LimeSurvey hosting: Own server 
Survey theme/template: fruity
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Dear all, 

I'm designing an SP experiment of travel mode choice. In my case, I'll let respondents report several stages of a journey, and ask them to choose the mode for certain stage(s) of that journey if they want. The stages of a journey are defined as subtrip before the main-trip, main trip, subtrip after the main trip. 

My question is: if respondents didn't report having the subtrip(s)  before and after the main trip, can I hide or exclude the row(s) of the "before" or "after"? I guess this should be a javascript issue? 

I've made a simple lss file and attached to this post, how this is clear for you. Thanks so much for your attention!