The issue looks like it is in the web app (without seeing your data or your select query). Did you follow all the instructions to create the web app script and to edit the manifest file correctly? Go back to the howto and compare what you have with what is there. Also, after any changes to your web app, you must publish/deploy a new version (and check that the script url remains the same if using the new editor).
For what it is worth, I tested the demo app I created and wrote the HOWTO from, and even created an entirely new web app from scratch. These both worked OK.
For a variety of reasons, I am using the legacy script editor (but this should not make any difference…)
1.Download the demo app from the link
2. Add the script codes and deploy it.
3. Then second code too in manifest file
4. Deploy again and copy the script url
5. Paste into the global variable
6. Add your sheet name into the variable, then test it. Simple
Well, I did it again and everything is working perfectly. I don’t understand what could have gone wrong the other time.
I’m adding values to my spreadsheet without any problems.
I’m looking for a guide where I can learn how to create a list that allows me to search for a specific value, change data and get the line number.
Well, I’m going to work on that. (Sorry SankaR, I couldn’t do it the way you told me). But I appreciate it.