This was prepared to help with a question posted on the Google Apps Script G+ forum. https://plus.google.com/110871587349095016187/posts/NTH6kg94QUr

findDateCellWithinADataRow.gs

function findDateCellWithinADataRow() {
  
  // Assumes an embedded script.
  var ss = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();
  
  // Pretend this is the way you want to get teh data
  // perhaps from the Google Form submission event.
  var row = ss.getRange(rowId, 1, 1, ss.getLastColumn());
  var rowValues = row.getValues()[0];
  
  // Pretend we are sure the date value always looks like this dd-mm-yyyy
  var datePattern = /(\d{1,2})-(\d{1,2})-(\d{4})/; 
  
  // Pretend we only need to get the date value from the first cell that matches
  var dateCells = rowValues
  .filter(function(cell){   
    return cell.match(datePattern);
  }).map(function(dateCell) {
    return (new Date(dateCell
                     .match(datePattern)
                     .slice(1)
                     .reverse()
                     .join('/'))); 
  });
  
  var firstDateCell = dateCells[0];
  
  debugger;
}