InsertDate Spreadsheet extenstion

InsertDate.gs

/**
 * The onOpen function runs automatically when the Google Docs document is
 * opened.
 *
 * More on `onOpen` and other trigger functions: https://developers.google.com/apps-script/guides/triggers/
 * More on `SpreadsheetApp` class: https://developers.google.com/apps-script/reference/spreadsheet/spreadsheet-app
 */
function onOpen() {
  // Add a menu with some items, some separators, and a sub-menu.
  SpreadsheetApp.getUi().createMenu('Utilities')
      .addItem('Insert Date', 'insertInCell')
      .addToUi();
}




/**
 * Inserts date into active cell.
 */
function insertInCell() {
  var cell = SpreadsheetApp.getActive().getActiveSheet().getActiveCell();

  if (cell) {
    // Attempt to insert text at the cursor position. If insertion returns null,
    // then the cursor's containing element doesn't allow text insertions.
    var date = Utilities.formatDate(new Date(), "GMT", "yyyy-MM-dd"); // "yyyy-MM-dd'T'HH:mm:ss'Z'"
    cell.setValue(date);
  } else {
    SpreadsheetApp.getUi().alert('Cannot find a cursor in the document.');
  }
}