Identifying empty lines of text

[David Epstein]

I use “the number of words in myString = 0” to test whether a line of text appears empty, since I want a line with only space characters to be understood as empty.
But a line of text I pasted from elsewhere contained an invisible character whose charToNum value is 202, and this was counted as a word by my script.
Is there a better way to test for a line of text that has no visible characters?
Many thanks.

David Epstein