VBA/javascript. script to automate browser actions

First of all. I'm a dummy in programming.

I was trying to use JavaScript and VBA in Excel to automate some IE actions to go to some page and download Excel files from that page, as I need to do this everyday.

1. The excel file to be downloaded does not have a link.

2. The VBA script did well in auto login, but when the IE goes to a second page ( different URL ), it always pops up a run time error 70 -- permission denied. I tried to modified the security in IE options but not working.

3. I use JavaScript to do the auto login and it worked well too, but again after the IE goes to a diff page, it seems stop working.

4. So I suspect that it might be that my script did not grab the new html document when url changes.

VBA:

Sub vbadownload()

Dim objIE As SHDocVw.InternetExplorer ' internet controls
Dim htmlDoc As MSHTML.HTMLDocument ' html object lib
Dim htmlInput As MSHTML.HTMLInputElement
Dim htmlDiv As MSHTML.HTMLDivElement
Dim htmlColl As MSHTML.IHTMLElementCollection    

Set objIE = New SHDocVw.InternetExplorer
''''''''''' first log in
With objIE
.Navigate "mainpage.com" ' log in page
.Visible = 1
Do While .READYSTATE <> 4: DoEvents: Loop
Application.Wait (Now + TimeValue("0:00:01"))

        'set user name and password
        Set htmlDoc = .Document
        Set htmlColl = htmlDoc.getElementsByTagName("INPUT")
        Do While htmlDoc.READYSTATE <> "complete": DoEvents: Loop
            For Each htmlInput In htmlColl
                If htmlInput.Name = "username" Then
                    htmlInput.Value = "xxxx"  'username
                Else
                    If htmlInput.Name = "password" Then
                        htmlInput.Value = "xxxx" 'password
                    End If
                End If
            Next htmlInput

        'click login
        Set htmlDoc = .Document
        Set htmlColl = htmlDoc.getElementsByTagName("input")
        Do While htmlDoc.READYSTATE <> "complete": DoEvents: Loop
            For Each htmlInput In htmlColl
                If Trim(htmlInput.Type) = "submit" Then
                     htmlInput.Click 'click
                     Exit For
                 End If
            Next htmlInput

' now it goes to second page after submit
' and I want click some button on second page, it says permission denied.
' so how do i make below codes work on current page without typing new url. ( as the url      actually does not change, I guess because it's js webpage? I don't know)

 Set htmlDoc = .Document
        Set htmlColl = htmlDoc.getElementsByTagName("div")
        Do While htmlDoc.READYSTATE <> "complete": DoEvents: Loop
            For Each htmlDiv In htmlColl
                If Trim(htmlDiv.ID) = "123" Then
                     htmlDiv.Click 'click
                     Exit For
                 End If
            Next htmlDiv
 End With

JavaScript

var ie = new ActiveXObject("InternetExplorer.Application");
ie.visible=true;
ie.navigate("www.sample.com");

while(ie.busy)(WScript.sleep(100));

var doc1 = ie.document;
var window1 = doc1.window;
var form1 = doc1.forms[0];

form1.username.value="xxx";
form1.password.value="xxxx";
form1.submit();


/* again, from here, it goes to second page, and it stops working.
* how do I get/parse current html document? */


var div1 = doc1.getElementsByTagName("div");


for (var i=0; i<div1.length; ++i)
{

if (div1[i].className="fff") 
 {div1[i].click()}
}