用于在现金明细表中自动求余额。这是用于Google Drive里电子表格(Spreadsheet)的脚本，使用Google Apps Script编写，类似于JavaScript。

sumBalance.js

function sumBalance() {
  var sheet = SpreadsheetApp.getActiveSheet();
  var rows = sheet.getDataRange();
  var numRows = rows.getNumRows();
  
  for (var i = 2; i <= numRows; i++) {
    var rowSum = 0;
    for (var j = 2; j <= i; j++) {
      rowSum = rowSum + sheet.getRange(j, 8, 1, 1).getValue();
    }
    
    sheet.getRange(i, 9, 1, 1).setValue(rowSum);
  }
}

/**
 * Adds a custom menu to the active spreadsheet, containing a single menu item
 * for invoking the readRows() function specified above.
 * The onOpen() function, when defined, is automatically invoked whenever the
 * spreadsheet is opened.
 * For more information on using the Spreadsheet API, see
 * https://developers.google.com/apps-script/service_spreadsheet
 */
function onOpen() {
  var sheet = SpreadsheetApp.getActiveSpreadsheet();
  var entries = [{
    name : "Sum Balance",
    functionName : "sumBalance"
  }];
  sheet.addMenu("Script Center Menu", entries);
};