How to Use DHTML with ASP and Long SQL Queries

ID: Q199233

The information in this article applies to:

Microsoft Internet Information Server versions 3.0, 4.0

SUMMARY

When SQL Server queries take a great deal of time to process in an ASP page, the Web browser may be left with a blank page while information is gathered from the database. If you use Internet Explorer's Dynamic HTML features, a message can be displayed to a Web browser while the data is processed and then changed or erased when the page is finished being rendered.

MORE INFORMATION

The following example ASP code uses a system Data Source Name (DSN) that points to the Adventure Works example Microsoft Access database that shipped with IIS 3.0, but can be tested with any data source by changing the following two lines:

strSQL = "SELECT * FROM <Table Name>"
RS.Open strSQL, "DSN=<Datasource Name>"

The following example page displays a message to the browser while loading the data, then changes that message to the record count after the data is loaded. Copy and save the following ASP code in your InetPub\Scripts folder as DhtmTest.asp, and then test the page by browsing to http://localhost/scripts/DhtmTest.asp.


   <html>
   <head><title>DHTML and ASP Example</title></head>
   <body>

   <h3 id="HideMe">Please wait while the data loads...</h3>

   <%
     Dim RS, strSQL, i
     Set RS = Server.CreateObject("ADODB.RecordSet")
     strSQL = "SELECT * FROM Products"
     RS.CursorType = 1 ' open with adOpenKeyset
     RS.Open strSQL, "DSN=AdvWorks"

     If Not RS.EOF Then
       Response.Write "<table border=1>" & vbCrLf

       Response.Write "<tr>"
       For i =  0 to (RS.Fields.Count - 1)
         Response.Write "<th>" & RS.Fields(i).Name & "</th>"
       Next
       Response.Write "</tr>" & vbCrLf
         
       Do While Not RS.EOF
         Response.Write "<tr>"
         For i =  0 to (RS.Fields.Count - 1)
           Response.Write "<td>" & RS.Fields(i).Value & "</td>"
         Next
         Response.Write "</tr>" & vbCrLf
         RS.MoveNext
       Loop

       Response.Write "</table>" & vbCrLf
     End If
   %>

   <script language="JavaScript" for="window" event="onload">
      HideMe.innerText='<%=RS.RecordCount%> Record(s) displayed.'
   </script>

   <% RS.Close %>

   </body>
   </html>

The above code can easily be modified to erase the message from the page by changing the script section to read as follows:


   HideMe.style.display='none';

Additional query words: jscript javascript scripting dhtml asp html

Keywords :
Version : winnt:3.0,4.0
Platform : winnt
Issue type : kbhowto