Google App Script - Conditional Formatting Based on Another Cell

Question

I am trying to figure out how to use conditional formatting via script on a google spreadsheet similar to what you can do with the conditional formatting feature.

I have

Answer 1

Let's assume that Country is placed at (1,1) and State is placed at (1,2) where (i,j) indicates the ith row and jth column on the Spreadsheet. Google Spreadsheets is 1-indexed meaning indices start at 1.

var activeSheet = SpreadsheetApp.getActiveSheet();

for (var a = 2; a < activeSheet.getLastRow(); a++) {
   if (String(activeSheet.getRange(a,1).getCell(1,1)) === "United States") { 
       if (String(activeSheet.getRange(a,2).getCell(1,1)) === null) { 
          activeSheet.getRange(a, 2, 1, 1).setBackgroundColor('red'); 
       } 
   } 
}