Newbie question re fields --> javascript

[David Brooks]

We are creating standalones and launching them in browsers. We have issues with taking in all of a field. Any help appreciated.

Works:
on mouseUp
   put "12131232" into myScore
   do "alert ('"  & myScore & "');" in browser
end mouseUp
   


Does NOT work:
on mouseUp
   put fld "ListOfFiles" into myScore
   do "alert ('"  & myScore & "');" in browser
end mouseUp


Works:
on mouseUp
   put line 1 of fld "ListOfFiles" into myScore
   do "alert ('"  & myScore & "');" in browser
end mouseUp

WE seem to be able to put in just one line. 

Thanks in advance for your help.