function trim(str) {
  return str.replace(/^\s+|\s+$/g, '');
};

function validate_email (trg) {
  var myValue = trim(trg.value);
  var testval = /^[a-zA-Z][a-zA-Z0-9\-\._]*\@([0-9a-zA-Z\-]{2,}\.)+([a-zA-Z]{2,3})+$/
  if(!testval.test(myValue)) {
    trg.className = trg.className + ' error';
    trg.value = myValue;
    trg.focus();
    return 'Please enter a valid email format e.g. xyz@abc.co.uk\n';
  } else { 
    var temp = trg.className;
    var rg = /error/gi;
    trg.className = temp.replace(rg,'');
    trg.value = myValue;
    return '';
  }
} // validate_email

function validate_completed (trg) {
  var myValue = trim(trg.value);
  if(myValue=='') {
    trg.className = trg.className + ' error';
    trg.value = myValue;
    trg.focus();
    return 'Please enter your name\n';
  } else { 
    var temp = trg.className;
    var rg = /error/gi;
    trg.className = temp.replace(rg,'');
    trg.value = myValue;
    return '';
  }
} // validate_email

function validate_form() {
  var err = '';
  err += validate_email(document.getElementById('email'));
  err += validate_completed(document.getElementById('name'));
  if(err == '') {
    return true;
  }
  alert(err);
  return false;
} // validate_form