Resizing a dynamic text box

1

i’m making a flash movie that’s going to load some text from a text file. i don’t know how long each of the variables within the text file will be though, so i need to resize the text box that they are going to be displayed it. is there anyway that i can do this so that all of the text is displayed and not cut off by the text box being too small - how do i know what size to make the text box? thanks