function checkRows( container_id, prefix ) {
  var rows = document.getElementById(container_id).getElementsByTagName('tr');
  var checkbox;

  for ( var i = 0; i < rows.length; i++ ) {
    checkbox = rows[i].getElementsByTagName( 'input' )[0];
    if ( checkbox && checkbox.type == 'checkbox' ) {
      if (checkbox.id.substring(0, prefix.length) == prefix)
      checkbox.checked = true;
    }
  }
  return true;
}

function uncheckAllRows( container_id ) {
  var rows = document.getElementById(container_id).getElementsByTagName('tr');
  var checkbox;

  for ( var i = 0; i < rows.length; i++ ) {
    checkbox = rows[i].getElementsByTagName( 'input' )[0];
    if ( checkbox && checkbox.type == 'checkbox' ) {
      checkbox.checked = false;
    }
  }
  return true;
}

function setCookie( cookieName, cookieValue, nDays ) {
  var today = new Date();
  var expire = new Date();

  if (nDays==null || nDays==0) nDays=1;
  expire.setTime(today.getTime() + 3600000*24*nDays);
  document.cookie = cookieName+"="+escape(cookieValue)+ ";expires="+expire.toGMTString();
}

function setBrowserWidthCookie() {
  var wsize = document.width;
//  var wsize = screen.width+'x'+screen.height;

  setCookie('browser_width', wsize, 1);
}

function checkEmail( email, email2, msg1, msg2 ) {
  var reg = /^[a-zA-Z0-9._-]+@[a-zA-Z0-9.-]{2,}[.][a-zA-Z]{2,3}$/

  if (reg.exec(email)==null) { alert(msg1); return false; }
  else {
    if (email != email2) { alert(msg2); return false; }
  }
  return true;
}

function checkPassword( passwd, passwd2, msg1, msg2 ) {
  if (passwd.length < 6) { alert(msg1); return false; }
  else {
    if (passwd != passwd2) { alert(msg2); return false; }
  }
  return true;
}

function checkNickname( nickname, msg1 ) {
  var reg = /^[a-zA-Z][a-zA-Z0-9]{3,19}$/

  if (reg.exec(nickname)==null) { alert(msg1); return false; }
  return true;
}