How to create one date variable from three form fields

<!--#include file="Q23565624-GeneralFunctions.asp"-->
 
<%	Dim dtNow, iLoop, sDisplay, sValue
	Dim sMonthFrom, sDayFrom, sYearFrom, iMonthFrom, iDayFrom, iYearFrom
	Dim sMonthTo, sDayTo, sYearTo, iMonthTo, iDayTo, iYearTo
	
	dtNow = Now()
	bIsPostback = (Request.Form("IsPostback") <> "")
	
	If NOT bIsPostback Then
		iMonthFrom = 1:  iDayFrom = 1:  iYearFrom = Year(dtNow)
		iMonthTo = Month(dtNow):  iDayTo = Day(dtNow):  iYearTo = Year(dtNow)
	Else
		sMonthFrom = Request.Form("monthfrom")
		sDayFrom = Request.Form("dayfrom")
		sYearFrom = Request.Form("yearfrom")
		sMonthTo = Request.Form("monthto")
		sDayTo = Request.Form("dayto")
		sYearTo = Request.Form("yearto")
 
		iMonthFrom = 0:  If IsPositiveInteger(sMonthFrom) Then iMonthFrom = CLng(sMonthFrom)
		iDayFrom = 0:  If IsPositiveInteger(sDayFrom) Then iDayFrom = CLng(sDayFrom)
		iYearFrom = 0:  If IsPositiveInteger(sYearFrom) Then iYearFrom = CLng(sYearFrom)
		iMonthTo = 0:  If IsPositiveInteger(sMonthFrom) Then iMonthTo = CLng(sMonthTo)
		iDayTo = 0:  If IsPositiveInteger(sDayFrom) Then iDayTo = CLng(sDayTo)
		iYearTo = 0:  If IsPositiveInteger(sYearFrom) Then iYearTo = CLng(sYearTo)
 
		If (iMonthFrom < 1) OR (iMonthFrom > 12) OR (iDayFrom < 1) OR (iDayFrom > 31) OR (iYearFrom < Year(dtNow)) Then
			Call Response.Write("One or more fields associated with your FROM date is invalid.<hr>" & vbNewLine)
		ElseIf (iMonthTo < 1) OR (iMonthTo > 12) OR (iDayTo < 1) OR (iDayTo > 31) OR (iYearTo < Year(dtNow)) Then
			Call Response.Write("One or more fields associated with your TO date is invalid.<hr>" & vbNewLine)
		ElseIf NOT IsDate(DateSerial(iYearFrom, iMonthFrom, iDayFrom)) Then
			Call Response.Write("Untrapped error -- FROM date could not be created.<hr>" & vbNewLine)
		ElseIf NOT IsDate(DateSerial(iYearTo, iMonthTo, iDayTo)) Then
			Call Response.Write("Untrapped error -- TO date could not be created.<hr>" & vbNewLine)
		Else
			Call Response.Write("FROM Date: [" & DateSerial(iYearFrom, iMonthFrom, iDayFrom) & "]<br>" & vbNewLine)
			Call Response.Write("TO Date: [" & DateSerial(iYearTo, iMonthTo, iDayTo) & "]<hr>" & vbNewLine)
		End If
	End If
%>
 
<form id="date" name="date" method="post" action="<%=Request.ServerVariables("SCRIPT_NAME")%>">
<input type="hidden" name="IsPostback" value="Yes">
      Select by Date Range: FROM: 
      <label>Day
      <select name="dayfrom" id="dayfrom">
<%	For iLoop = 1 to 31
		sValue = iLoop
		sDisplay = iLoop
		bSelected = False:  If (iDayFrom = iLoop) Then bSelected = True %>
			<option value="<%=sValue%>"<% if bSelected then %> selected="selected"<% end if %>><%=sDisplay%></option>
<%	Next %>
      </select>
      </label>
        <label>Month
        <select name="monthfrom" id="monthfrom">
<%	For iLoop = 1 to 12
		sValue = iLoop:  If (iLoop < 10) Then sValue = "0" & sValue
		sDisplay = MonthName(iLoop)
		bSelected = False:  If (iMonthFrom = iLoop) Then bSelected = True %>
			<option value="<%=sValue%>"<% if bSelected then %> selected="selected"<% end if %>><%=sDisplay%></option>
<%	Next %>
        </select>
        </label>
        <label>Year
        <select name="yearfrom" id="yearfrom">
<%	For iLoop = Year(dtNow) to Year(dtNow)+2
		sValue = iLoop
		sDisplay = iLoop
		bSelected = False:  If (iYearFrom = iLoop) Then bSelected = True %>
			<option value="<%=sValue%>"<% if bSelected then %> selected="selected"<% end if %>><%=sDisplay%></option>
<%	Next %>
        </select>
        </label>
    TO: <label>Day
      <select name="dayto" id="dayto">
<%	For iLoop = 1 to 31
		sValue = iLoop
		sDisplay = iLoop
		bSelected = False:  If (iDayTo = iLoop) Then bSelected = True %>
			<option value="<%=sValue%>"<% if bSelected then %> selected="selected"<% end if %>><%=sDisplay%></option>
<%	Next %>
      </select>
      </label>
        <label>Month
        <select name="monthto" id="monthto">
<%	For iLoop = 1 to 12
		sValue = iLoop:  If (iLoop < 10) Then sValue = "0" & sValue
		sDisplay = MonthName(iLoop)
		bSelected = False:  If (iMonthTo = iLoop) Then bSelected = True %>
			<option value="<%=sValue%>"<% if bSelected then %> selected="selected"<% end if %>><%=sDisplay%></option>
<%	Next %>
        </select>
        </label>
        <label>Year
        <select name="yearto" id="yearto">
<%	For iLoop = Year(dtNow) to Year(dtNow)+2
		sValue = iLoop
		sDisplay = iLoop
		bSelected = False:  If (iYearTo = iLoop) Then bSelected = True %>
			<option value="<%=sValue%>"<% if bSelected then %> selected="selected"<% end if %>><%=sDisplay%></option>
<%	Next %>
        </select>
        </label>
        <label>
        <input type="submit" name="Submit" value="Submit" />
        </label>
        <p></p>
    </form>

                                              

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