javascript paragraph formatting in form text field

Hi - I am new with javascript and seem to be hitting a bunch of dead ends. I am trying to create a form with multiple check boxes, Based on the selection of text boxes a full letter will populate. Right now I am using scrip that looks like this 

var a = this.getField("options").value;
if(a == "a"){
event.value = "Option A paragraph";
}
else if(a == "b"){
event.value = "Options B paragraph";
}

I have done this script for all 10 chck boxes and have 10 coressponding text box fields to popoulate the informaton in. 

But I am now realizing that the paragraph options are all different lengths and the letter would have to be formatted each time. 

Is there a script that would auto format all the paragraph spacing? or should I use one big long text box (but it would have to be multiple pages) with a long script. 

Last question: can you format paragraphs with javascript ?

Thank you