javascript做的日历，完全对象化，望高手提出改进意见。（2/3，将3部分拼成一个html文件浏览）

  this.gettextdate = function(thestring){ //convert a string to a date, if the string is not a date, return a empty string
    var i = 0, tmpchar = "", find_tag = "";
    var start_at = 0, end_at = 0, year_at = 0, month_at = 0, day_at = 0;
    var tmp_at = 0, one_at = 0, two_at = 0, one_days = 0, two_days = 0;
    var arydate = new array();
    var tmpyear = -1, tmpmonth = -1, tmpday = -1;
    var tmpdate = thestring.tolowercase();
    var defdate = "";
    end_at = tmpdate.length;
    for (i=1;i<end_at;i++){
      if (tmpdate.charat(i)=="0"){
        tmpchar = tmpdate.charat(i-1);
        if (tmpchar<"0" || tmpchar>"9"){
          tmpdate = tmpdate.substr(0,i-1) + "-" + tmpdate.substr(i+1);
        }
      }
    }
    for (i=0;i<9;i++){
      tmpdate = tmpdate.replace(this.monthname[i].tolowercase().substr(0,3), "-00" + (i+1).tostring() + "-");
    }
    for (i=9;i<12;i++){
      tmpdate = tmpdate.replace(this.monthname[i].tolowercase().substr(0,3), "-0" + (i+1).tostring() + "-");
    }
    tmpdate = tmpdate.replace(/jan/g, "-001-");
    tmpdate = tmpdate.replace(/feb/g, "-002-");
    tmpdate = tmpdate.replace(/mar/g, "-003-");
    tmpdate = tmpdate.replace(/apr/g, "-004-");
    tmpdate = tmpdate.replace(/may/g, "-005-");
    tmpdate = tmpdate.replace(/jun/g, "-006-");
    tmpdate = tmpdate.replace(/jul/g, "-007-");
    tmpdate = tmpdate.replace(/aug/g, "-008-");
    tmpdate = tmpdate.replace(/sep/g, "-009-");
    tmpdate = tmpdate.replace(/oct/g, "-010-");
    tmpdate = tmpdate.replace(/nov/g, "-011-");
    tmpdate = tmpdate.replace(/dec/g, "-012-");
    for (i=0;i<tmpdate.length;i++){
      tmpchar = tmpdate.charat(i);
      if ((tmpchar<"0" || tmpchar>"9") && (tmpchar != "-")){
        tmpdate = tmpdate.replace(tmpchar,"-")
      }
    }
    while(tmpdate.indexof("–") != -1){
      tmpdate = tmpdate.replace(/–/g,"-");
    }
    start_at = 0;
    end_at = tmpdate.length-1;
    while (tmpdate.charat(start_at)=="-"){
      start_at++;
    }
    while (tmpdate.charat(end_at)=="-"){
      end_at–;
    }
    if (start_at < end_at+1){
      tmpdate = tmpdate.substring(start_at,end_at+1);
    }else{
      tmpdate = "";
    }
    arydate = tmpdate.split("-");
    if (arydate.length != 3){
      return(defdate);
    }
    for (i=0;i<3;i++){
      if (parseint(arydate[i],10)<1){
        arydate[i] = "1";
      }
    }
    find_tag="000";
    for (i=2;i>=0;i–){
      if (arydate[i].length==3){
        if (arydate[i]>="001" && arydate[i]<="012"){
          tmpmonth = parseint(arydate[i],10)-1;
          switch (i){
            case 0:
              find_tag = "100";
              one_at = parseint(arydate[1],10);
              two_at = parseint(arydate[2],10);
              break;
            case 1:
              find_tag = "010";
              one_at = parseint(arydate[0],10);
              two_at = parseint(arydate[2],10);
              break;
            case 2:
              find_tag = "001";
              one_at = parseint(arydate[0],10);
              two_at = parseint(arydate[1],10);
              break;
          }
        }
      }
    }
    if (find_tag!="000"){
      one_days = this.getmonthdays(two_at,tmpmonth);
      two_days = this.getmonthdays(one_at,tmpmonth);
      if ((one_at>one_days)&&(two_at>two_days)){
        return(defdate);
      }
      if ((one_at<=one_days)&&(two_at>two_days)){
        tmpyear = this.getformatyear(two_at);
        tmpday = one_at;
      }
      if ((one_at>one_days)&&(two_at<=two_days)){
        tmpyear = this.getformatyear(one_at);
        tmpday = two_at;
      }
      if ((one_at<=one_days)&&(two_at<=two_days)){
        tmpyear = this.getformatyear(one_at);
        tmpday = two_at;
        tmpdate = this.dateformat;
        year_at = tmpdate.indexof("<yyyy>");
        if (year_at == -1){
          year_at = tmpdate.indexof("<yy>");
        }
        day_at = tmpdate.indexof("<dd>");
        if (day_at == -1){
          day_at = tmpdate.indexof("<d>");
        }
        if (year_at >= day_at){
          tmpyear = this.getformatyear(two_at);
          tmpday = one_at;
        }
        }
      return(new date(tmpyear, tmpmonth, tmpday));
    }
    find_tag = "000";
    for (i=2;i>=0;i–){
      if (parseint(arydate[i],10)>31){
        tmpyear = this.getformatyear(parseint(arydate[i],10));
        switch (i){
          case 0:
            find_tag = "100";
            one_at = parseint(arydate[1],10);
            two_at = parseint(arydate[2],10);
            break;
          case 1:
            find_tag = "010";
            one_at = parseint(arydate[0],10);
            two_at = parseint(arydate[2],10);
            break;
          case 2:
            find_tag = "001";
            one_at = parseint(arydate[0],10);
            two_at = parseint(arydate[1],10);
            break;
        }
      }
    }
    if (find_tag=="000"){
      tmpdate = this.dateformat;
      year_at = tmpdate.indexof("<yyyy>");
      if (year_at == -1){
        year_at = tmpdate.indexof("<yy>");
      }
      month_at = tmpdate.indexof("<mmmmmm>");
      if (month_at == -1){
        month_at = tmpdate.indexof("<mmm>");
      }
      if (month_at == -1){
        month_at = tmpdate.indexof("<mm>");
      }
      if (month_at == -1){
        month_at = tmpdate.indexof("<m>");
      }
      day_at = tmpdate.indexof("<dd>");
      if (day_at == -1){
        day_at = tmpdate.indexof("<d>");
      }
      if ((year_at>month_at)&&(year_at>day_at)){
        find_tag="001"
      }
      if ((year_at>month_at)&&(year_at<=day_at)){
        find_tag="010";
      }
      if ((year_at<=month_at)&&(year_at>day_at)){
        find_tag="010";
      }
      if ((year_at<=month_at)&&(year_at<=day_at)){
        find_tag="100";
      }
      switch (find_tag){
        case "100":
          tmpyear = parseint(arydate[0],10);
          one_at = parseint(arydate[1],10);
          two_at = parseint(arydate[2],10);
          break;
        case "010":
          one_at = parseint(arydate[0],10);
          tmpyear = parseint(arydate[1],10);
          two_at = parseint(arydate[2],10);
          break;
        case "001":
          one_at = parseint(arydate[0],10);
          two_at = parseint(arydate[1],10);
          tmpyear = parseint(arydate[2],10);
          break;
      }
      tmpyear = this.getformatyear(tmpyear);
    }
    if (find_tag!="000"){
      if ((one_at>12)&&(two_at>12)){
        return(defdate);
      }
      if (one_at<=12){
        if (two_at > this.getmonthdays(tmpyear,one_at-1)){
          return(new date(tmpyear, one_at-1, this.getmonthdays(tmpyear,one_at-1)));
        }
        if (two_at>12){
          return(new date(tmpyear, one_at-1, two_at));
        }
      }
      if (two_at<=12){
        if (one_at > this.getmonthdays(tmpyear,two_at-1)){
          return(new date(tmpyear, two_at-1, this.getmonthdays(tmpyear,two_at-1)));
        }
        if (one_at>12){
          return(new date(tmpyear, two_at-1, one_at));
        }
      }
      if ((one_at<=12)&&(two_at<=12)){
        tmpmonth = one_at-1;
        tmpday = two_at;
        tmpdate = this.dateformat;
        month_at = tmpdate.indexof("<mmmmmm>");
        if (month_at == -1){
          month_at = tmpdate.indexof("<mmm>");
        }
        if (month_at == -1){
          month_at = tmpdate.indexof("<mm>");
        }
        if (month_at == -1){
          month_at = tmpdate.indexof("<m>");
        }
        day_at = tmpdate.indexof("<dd>");
        if (day_at == -1){
          day_at = tmpdate.indexof("<d>");
        }
        if (month_at >= day_at){
          tmpmonth = two_at-1;
          tmpday = one_at;
        }
         return(new date(tmpyear, tmpmonth, tmpday));
      }
    }
  }
  this.createyearlist = function(minyear, maxyear){ //create year list
    var thename = this.name;
    var theyearobject = document.all.item(thename + "_yearlist");
    if (theyearobject == null){
      return;
    }
    var theyear = 0;
    var theyearhtml = "<select id=\"" + thename + "_yearlist\" style=\"" + this.yearliststyle + "\" tabindex=\"-1\" onchange=\"document.jsmonthview.updatemonthgrid(this)\" onblur=\"document.jsmonthview.deletemonthgrid()\">";
    for (theyear = minyear; theyear <= maxyear; theyear++){
      theyearhtml += "<option value=\"" + theyear.tostring() + "\">" + theyear.tostring() + "</option>";
    }
    theyearhtml += "</select>";
    theyearobject.outerhtml = theyearhtml;
  }
  this.createmonthlist = function( ){ //create month list
    var thename = this.name;
    var themonthobject = document.all.item(thename + "_monthlist");
    if (themonthobject == null){
      return;
    }
    var themonth = 0;
    var themonthhtml = "<select id=\"" + thename + "_monthlist\" style=\"" + this.monthliststyle + "\" tabindex=\"-1\" onchange=\"document.jsmonthview.updatemonthgrid(this)\" onblur=\"document.jsmonthview.deletemonthgrid()\">";
    for (themonth = 0; themonth < 12; themonth++){
      themonthhtml += "<option value=\"" + themonth.tostring() + "\">" + this.monthname[themonth] + "</option>";
    }
    themonthhtml +="</select>";
    themonthobject.outerhtml = themonthhtml;
  }
  this.setdaylist = function(theyear, themonth, theday){ //set the month view show a date
    var thename = this.name;
    var thedayobject = document.all.item(thename + "_daylist");
    if (thedayobject == null){
      return;
    }
    thedayobject.value = theday.tostring();
    var thefirstday = new date(theyear, themonth, 1);
    var thecurrentdate = new date();
    var theweek = thefirstday.getday();
    if (theweek == 0){
      theweek = 7;
    }
    var theleftday = 0;
    if (themonth == 0){
      theleftday = 31;
    }else{
      theleftday = this.getmonthdays(theyear, themonth – 1);
    }
    var therightday = this.getmonthdays(theyear, themonth);
    var thecurrentday = theleftday – theweek + 1;
    var offsetmonth = -1; //the month is previous month
    var thecolor = this.invalidcolor;
    var thebgcolor = this.unselectbgcolor;
    var thebdcolor = thebgcolor;
    var weekid = 0
    var dayid = 0;
    var thestyle = "";
    var thedayhtml = "<table width=\"100%\" height=\"100%\" border=\"0\" cellspacing=\"0\" cellpadding=\"0\">";
    thedayhtml += "        <tr style=\"" + this.titlestyle + "\">";
    for (dayid = 0; dayid < 7; dayid++){
      thedayhtml += "        <td width=\"10%\">" + this.weekname[dayid] + "</td>";
    }
    thedayhtml += "        </tr>";
    thedayhtml += "        <tr>";
    thedayhtml += "            <td colspan=\"7\" style=\"" + this.linebgstyle + "\">";
    thedayhtml += "                <table style=\"" + this.linestyle + "\" border=\"0\" cellspacing=\"0\" cellpadding=\"0\">";
    thedayhtml += "                    <tr><td></td></tr>";
    thedayhtml += "                </table>";
    thedayhtml += "            </td>";
    thedayhtml += "        </tr>";
    for (weekid = 0; weekid < 6; weekid++){
      thedayhtml += "    <tr style=\"" + this.daystyle + "\">";
      for (dayid = 0; dayid < 7; dayid++){
        if ((thecurrentday > theleftday) && (weekid < 3)){
          offsetmonth++; //the month is current month;
          thecurrentday = 1;
        }
        if ((thecurrentday > therightday) && (weekid > 3)){
          offsetmonth++; //the month is next month;
          thecurrentday = 1;
        }
        switch (offsetmonth){
          case -1:
            thecolor = this.invalidcolor;
            break;
        case 1:
            thecolor = this.invalidcolor;
            break;
        case 0:
            if ((dayid==0)||(dayid==6)){
              thecolor = this.weekendcolor;
            }else{
              thecolor = this.validcolor;
            }
            break;
        }
        if ((dayid==0)||(dayid==6)){
          thebgcolor = this.weekendbgcolor;
        }else{
          thebgcolor = this.unselectbgcolor;
        }
        thebdcolor = this.daybdcolor;
        if ((thecurrentday == theday) && (offsetmonth == 0)){
          thecolor = this.selectedcolor;
          thebgcolor = this.selectedbgcolor;
          thebdcolor = thebgcolor;
        }
        if ((theyear == thecurrentdate.getfullyear()) && (themonth == thecurrentdate.getmonth()) && (thecurrentday == thecurrentdate.getdate()) && (offsetmonth == 0)){
          thebdcolor = this.todaybdcolor;
        }
        thestyle = "border:" + this.daybdwidth + "px solid " + thebdcolor + "; color:" + thecolor + "; background-color:" + thebgcolor + ";";
        thedayhtml += "        <td style=\"" + thestyle + "\" onmouseover=\"" + this.overdaystyle + "\" onmouseout=\"" + this.outdaystyle + "\" onmousedown=\"document.jsmonthview.createmonthgrid(" + theyear.tostring() + ", " + (themonth + offsetmonth).tostring() + ", " + thecurrentday.tostring() + ")\">";
        thedayhtml += thecurrentday.tostring();
        thedayhtml += "        </td>";
        thecurrentday++;
      }
      thedayhtml += "    </tr>";
    }
    thedayhtml += "        <tr style=\"" + this.footerstyle + "\" onmousedown=\"document.jsmonthview.createmonthgrid(" + thecurrentdate.getfullyear().tostring() + ", " + thecurrentdate.getmonth().tostring() + ", " + thecurrentdate.getdate().tostring() + ");\">";
    thestyle = "border:" + this.daybdwidth + "px solid " + this.todaybdcolor + ";";
    thedayhtml += "            <td style=\"" + thestyle + "\"><br></td>";
    thedayhtml += "            <td colspan=\"6\"> " + this.todaytitle + " " + this.setdateformat(thecurrentdate.getfullyear(), thecurrentdate.getmonth(), thecurrentdate.getdate()) + "</td>";
    thedayhtml += "        </tr>";
    thedayhtml += "    </table>";
    var themonthgrid = document.all.item(thename + "_monthgrid");
    themonthgrid.innerhtml = thedayhtml;
  }