chatGPT is unable to answer: why VBScript's do until ... loop can be written in multiple<% %> code blocks?

VBScript do until ... loop being written in multiple <% %> code blocks.

<select id="TaskID" name="TaskID" onChange="javascript: changeReportType(); OnClientsByAdviserReportSelected();">
    <% prReports.MoveFirst()
    Do Until prReports.AtEnd()
        If CastDec(prReports("Requestable")) = 1D Then %>
            <option <% If Convert.ToString(pnTaskID) = prReports("TaskID") Then %> selected <% End If %> 
            value="<%: prReports("TaskID").ToString & "-" & prReports("ReportName").ToString %>">
                <%: prReports("DisplayName") %>
            </option>
        <% End If
        prReports.MoveNext()
    Loop %>
</select>

Recently, I've read this code block above in a .aspx file. This is an old project that need to be maintaining.
I was astonished by the style of the code. Because the do until ... loop is written in multiple <%%> blocks for inserting more <option> labels. That means the <%%> blocks break the complete code logic. I've searching for the explanation, but I got nothing on google yet. I've asked chatGPT and got the answer what the code doing but no more in-depth explanation. I wonder there are some one understand why the code can be written into multiple <%%> code blocks.

how does it work and its in-depth explanation.

Is this a webforms application?

That being the case, then that looks to be vb.net code.

Really, like Pascal, C# or whatever? Think of the "<%" as a starting of a code block, and the "%>" as the end of a code block.

So, I could write some server-side code, place it in the markup like this:

        <% 
            Dim i As Integer
            Dim j As Integer = 1
            For i = 1 To 10
                Response.Write(i & "<br/>")
                j = j + 5
            Next

            Response.Write("<br/>")
            Response.Write("<br/>")
            Response.Write("<br/>")
            Response.Write("Total for j = " & j)

        %>

In above have some br's etc. With more complex markup, then it often becomes “difficult" to write such code in vb.net.

So, some of the markup can remain client-side markup. (Anything outside of an open + closing tag of <% server code here %> then client-side markup follows.

So, above could be written like this:

<% Dim i As Integer %>
<% Dim j As Integer = 1 %>
<% For i = 1 To 10
        Response.Write(i) %> <br/>
<%  j = j + 5 %>
<%  Next %>
<br />
<br />
<br />
Total for j = <% Response.Write(j) %>

So, in above, I choose to have "more" markup (client side), and thus I have to start server-side code, close the server code tag, and what follows is now regular client-side markup.

Both of above examples produces the same results:

Keep in mind, you can do this when writing c#, or vb.net.

However, I think web forms markup is already rather crowded, and thus very little reasons exists to inter-mix server code in markup when you have a nice clean code behind code module.

Thus rare does one need to write code blocks in the markup section of an aspx page. However, using expressions in the markup is a common practice.

Note that you can do the above if this is a C# application.

So, above could be written as this when using C#:

<% int i;%>
<% int j = 1;%>
<% for (i = 1;i <= 10;i++)
    {
        Response.Write(i.ToString()); %> <br />
<%      j = j + 5;
    }
 %>
<br />
<br />
<br />
Total for j = <% Response.Write(j); %>

So, you not limited to using above with vb.net, and the same approach and option is available when writing code in C#.