how to find location of specific <tr> each time code is run - html

Question

My code below will extract a value for each hour of the day.
However, the webpage I'm scraping can change and so I want to find a way to assign the location of the to a variable so that it will know what number it is everytime. I found the current number "116" by trial and error.
I included the html structure below as well. Any suggestions?
Sub scrape()
Dim IE As Object
Set IE = CreateObject("InternetExplorer.application")
With IE
.Visible = False
.navigate "web address"
Do Until .readyState = 4
DoEvents
Loop
.document.all.item("Login1_UserName").Value = "user"
.document.all.item("Login1_Password").Value = "pw"
.document.all.item("Login1_LoginButton").Click
Do Until .readyState = 4
DoEvents
Loop
End With
Dim htmldoc As Object
Dim r
Dim c
Dim aTable As Object
Dim TDelement As Object
Set htmldoc = IE.document
Dim td As Object
For Each td In htmldoc.getElementsByTagName("td")
On Error Resume Next
If span.Children(0).id = "ctl00_PageContent_grdReport_ctl08_Label50" Then
ThisWorkbook.Sheets("sheet1").Range("j8").Offset(r, c).Value = td.Children(1).innerText
End If
On Error GoTo 0
Next td
End Sub
HTML:
<form name="aspnetForm" id="aspnetForm" action="./MinMaxReport.aspx"
method="post">
<div>
</div>
<script type="text/javascript">...</script>
<div>
</div>
<table class="header-table">...</table>
<table class="page-area">
<tbody>
<tr>
<table id="ctl00_PageContent_Table1" border="0">...</table>
<table id="ctl00_PageContent_Table2" border="0">
<tbody>
<tr>
<td>
<div id="ctl00_PageContent_grdReport_div">
<tbody>
<tr style="background-color: beige;">
<td>...</td>
<td>
<span id="ctl00_PageContent_grdReport_ctl08_Label50">Most Restrictive
Capacity Maximum</span>
</td>
<td>
<span id="ctl00_PageContent_grdReport_ctl08_Label51">159</span>
</td>
</tr>
</tbody>
</div>
</td>
</tr>
</tbody>
</table>
</table>
</tr>
</tbody>
</table>

Answer 1

You could loop through all TDs and check if id= "ctl00_PageContent_grdReport_ctl08_Label50" for example:
For Each td In htmldoc.getElementsByTagName("td")
On Error Resume Next
If td.Children(0).ID = "ctl00_PageContent_grdReport_ctl08_Label50" Then
ThisWorkbook.Sheets("sheet1").Range("j8").Offset(r, c).Value = td.Children(1).innerText
End If
On Error GoTo 0
Next td
Children(0) will pick the first iHTML element contained in your table cell. On Error Resume Next is for the situation when td element has no child.
It is possible that you have more then one element with this id in your webpage. Then, you must identify table or table row first. I cannot do it because I can't see your whole HTML code.