//ユーザが設定する変数----------------------------------
  //対象となるフォームの要素のIDを順番に
  var target = new Array();
  target[0] = "adress1";
  target[1] = "adress2";
  target[2] = "area1";
  //対象となるフォームの要素の文字数の最大値
  var focus = new Array();
  focus[0] = 3;
  focus[1] = 4;
//------------------------------------------------------

function next(n){
  if (document.getElementById){
    f = document.getElementById(target[n]).value;
    if (f.length < focus[n]) return true;
    document.getElementById(target[n]).blur();
    document.getElementById(target[n+1]).focus();
  }
}