function form_submit(competition_id) {
  var frm = document.getElementById('frm'+competition_id);
  var ans = document.getElementById('answer'+competition_id);
  if (ans.value.length<1) {
  	alert('To stand a chance of winning you have to answer the question.');
  	ans.focus();
  	return false;
  } else {
  	frm.submit();
  }
  
}

function competitionEntered(competition_id) {
  var buttonBlock = document.getElementById('buttonBlock'+competition_id);
  buttonBlock.innerHTML = "Thank-you, we've received your entry.";
}