for Tampermonkey

gistfile1.js

// ==UserScript==
// @name railwayTicketFormAutoField
// @namespace http://railway.hinet.net/ctno1.htm
// @description Change some element on login page
// @include http://*railway.hinet.net/ctno1.htm
// ==/UserScript==


var personalId = 'A123456789';  // 身份正字號
var fromStation = '100';   // 台北
var toStation = '129';    // 台中港
var trainNo = '111';      // 車次

// 乘車日期、訂票張數需要手動改一下



var form = document.forms['ctno1'];
form['person_id'].value = personalId;

var selection = document.getElementsByName('from_station')[0];
for(var index in selection.options){
 if(selection.options[index].value == fromStation){
   selection.options[index].setAttribute('selected');
 }
}

var selection = document.getElementsByName('to_station')[0];
for(var index in selection.options){
 if(selection.options[index].value == toStation){
   selection.options[index].setAttribute('selected');
 }
}

var selection = document.getElementsByName('getin_date')[0];
for(var index in selection.options){
  var val = '' + selection.options[index].value;
  
  if( val != undefined ){
      console.log(val);
    if( val.match(/2014\/01\/18/) ){   // 日期
        console.log(val);
       selection.options[index].setAttribute('selected');
    }
  }
}

form['train_no'].value = trainNo;