Untitled

function formatPctThreeSigFigs() {

  /* Formats selected numeric cells as a percentage with three significant figures.
   *
   * Author: Raneath Nor (raneath@gmail.com)
   * Date:   5/31/2011
   */

  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var range = ss.getActiveRange();

  var rows = range.getNumRows();
  var cols = range.getNumColumns();
  for(var row = 1; row <= rows; row++) {
    for(var col = 1; col <= cols; col++) {
      var cell = range.getCell(row, col);
      var value = cell.getValue();
      if(typeof(value) == 'number') {
        cell.setNumberFormat("#.###%");
      }
    }
  }
}