There seems to be a limit on the number of nested tables in browsers, I think.

IE stops at 25, FireFox stops at 31.

Place the following in a webform in Visual Studio, after the @Page directive:

Code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
	<HEAD>
		<title>WebForm1</title>
		<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
		<meta name="CODE_LANGUAGE" Content="C#">
		<meta name="vs_defaultClientScript" content="JavaScript">
		<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
	</HEAD>
	<body MS_POSITIONING="GridLayout">
		<form id="Form1" method="post" runat="server">
			<asp:Button id="Button1" style="Z-INDEX: 101; LEFT: 128px; POSITION: absolute; TOP: 80px" runat="server"
				Text="Button"></asp:Button>
			<asp:PlaceHolder id="phTables" runat="server"></asp:PlaceHolder>
		</form>
	</body>
</HTML>
In the codebehind,

Code:
		private void Button1_Click(object sender, System.EventArgs e)
		{
			
			this.phTables.Controls.Add(AddHTMLTableControl(50));

		}

		private Table AddHTMLTableControl(int level)
		{
 
			Table t = new Table();
			t.Width = Unit.Percentage(100);
			t.Height = Unit.Point(100);
			t.BorderWidth = 1;
			TableRow tr = new TableRow();
			TableCell tc = new TableCell();
			tr.Cells.Add(tc);
			t.Rows.Add(tr);
			for (int i = 0; i < level; i++)
			{
				Table t1 = new Table();
				t1.Width = Unit.Percentage(100);
				t1.Height = Unit.Point(100);
				t1.BorderWidth = 1;
				TableRow tr1 = new TableRow();
				TableCell tc1 = new TableCell();
				Label lbl = new Label();
				lbl.Text = "level" + i;
				// lbl.Width = 26;
				tc1.Controls.Add(lbl);
				tr1.Cells.Add(tc1);
				t1.Rows.Add(tr1);
				tc.Controls.Add(t1);
				tc = tc1;
			}
			return t;
		}
Now, run the page, click on the button.

Why the limit?