Triggers (onEdit, onOpen) in Google Sheets - Cell-by-Cell Formula Trace

Sample Data

A simple score table with names and scores.

Cell	Value
A1	Name
B1	Score
A2	Alice
B2	85
A3	Bob
B3	90
A4	Charlie
B4	78

Formula Trace

onEdit(e) and onOpen() are Google Sheets triggers that run scripts automatically when you edit a cell or open the spreadsheet.

Step 1: User edits cell B2 from 85 to 88

Step 2: Script reads the edited cell B2 value (88)

Step 3: Script updates cell C2 with 'Updated!'

Step 4: User opens the spreadsheet

Step 5: Script adds a custom menu 'My Menu' to the spreadsheet UI

Cell Reference Map

Name

↓

Alice

↓

Bob

↓

Charlie

Cells A1:B4 hold data. Cell B2 is edited triggering onEdit. Cell C2 is updated by script. onOpen affects the whole spreadsheet UI.

Result

   A       B       C
1 Name    Score   
2 Alice   88     Updated!
3 Bob     90     
4 Charlie 78     

Menu: 'My Menu' appears in toolbar

After editing B2 to 88, cell C2 shows 'Updated!'. When the sheet opens, a custom menu 'My Menu' appears in the toolbar.

Sheet Trace Quiz - 3 Questions

What event causes the onEdit trigger to run?

A When a user changes a cell value

B When the spreadsheet is opened

C When a formula recalculates

D When a new sheet is added

Key Result

Triggers like onEdit and onOpen run scripts automatically on user actions like editing cells or opening the sheet.