Dear Code A, yes, when I copied Michael’s syntax exactly, the code did not work. So I browse through the forum and found some coding related to text labels. It seems to me that double quotation marks and a close bracket are needed. After adding those 2, the code worked. In my learning of M1, I benefited much from the info on this forum and thought to correct this “if it was a mistake” so that others may benefit in the same way I did. But based on your reply, it seems Michael’s coding is correct and should work…
To confirm the answer to my 2nd question, as long as I use this ID method, I need not reference the mobi filename in the code even if I may have multiple mobi files in 1 app ? I need to clarify further that I am putting this javascript code in the main_custom.js file, meaning pressing the number button in my calculator project will call up a javascript function which ultimately will do some calculations writing results to the text label.