查询后如何保持下拉框中年月日的值(年,月的值可保存,日期搞不定)

  如标题,这是做的一个动态下拉联动,日期的值根据月份的不同作相应变化,现在问题是点击查询后下拉框中无法保存所选择日期的值,请问各位大虾如何解决?
  附主要代码:
  这是脚本:

  <script language="javascript1.2">

function changeDay(yObj, mObj, dObj) {
  var arr28 = [["00","--- Select Date ---"],["01","01"],["02","02"],["03","03"],["04","04"],["05","05"],["06","06"],["07","07"],["08","08"],["09","09"],["10","10"],["11","11"],["12","12"],["13","13"],["14","14"],["15","15"],["16","16"],["17","17"],["18","18"],["19","19"],["20","20"],["21","21"],["22","22"],["23","23"],["24","24"],["25","25"],["26","26"],["27","27"],["28","28"]];
  var arr29 = [["00","--- Select Date ---"],["01","01"],["02","02"],["03","03"],["04","04"],["05","05"],["06","06"],["07","07"],["08","08"],["09","09"],["10","10"],["11","11"],["12","12"],["13","13"],["14","14"],["15","15"],["16","16"],["17","17"],["18","18"],["19","19"],["20","20"],["21","21"],["22","22"],["23","23"],["24","24"],["25","25"],["26","26"],["27","27"],["28","28"],["29","29"]];
  var arr30 = [["00","--- Select Date ---"],["01","01"],["02","02"],["03","03"],["04","04"],["05","05"],["06","06"],["07","07"],["08","08"],["09","09"],["10","10"],["11","11"],["12","12"],["13","13"],["14","14"],["15","15"],["16","16"],["17","17"],["18","18"],["19","19"],["20","20"],["21","21"],["22","22"],["23","23"],["24","24"],["25","25"],["26","26"],["27","27"],["28","28"],["29","29"],["30","30"]];
  var arr31 = [["00","--- Select Date ---"],["01","01"],["02","02"],["03","03"],["04","04"],["05","05"],["06","06"],["07","07"],["08","08"],["09","09"],["10","10"],["11","11"],["12","12"],["13","13"],["14","14"],["15","15"],["16","16"],["17","17"],["18","18"],["19","19"],["20