How to hide the refresh button on the report viewer control (ASP.NET)

Firstly, don't mix DOM0 inline event handlers with jQuery. Separate your markup and your logic.

If you use a data- attribute you can put your variable's content in your HTML, and then extract that in the event handler:

<a id="test" data-foo="mytitle" href="#">Testlink</a>

and then:

$(document).ready(function() {
    $('#test').on('click', function() {
        alert($(this).data('foo'));
    }
});

In this code the alert won't appear until the link is actually clicked on, of course.

You could use a System.Threading.Timer to do this. Instead of a loop that constantly runs and sleeps, you could set the interval to the Timer to be the difference between now and the selected time and the TimerCallback to be the Sub that does the task work. Setting the timeout to 0 or Timeout.Infinite will make sure this is only executed once.

EDIT: Example

Dim tcb As TimerCallback = AddressOf DoStuff
Dim t As Timer
Dim execTime As TimeSpan
Dim dtNow As DateTime = DateTime.Now
Dim hc As Integer = HourChoice
Dim mc As Integer = MinuteChoice

If TimeOfDay = "AM" And hc = 12 Then
    hc = 0
Else If TimeOfDay = "PM" Then
    hc = hc + 12
End If

Dim dtCandidate As DateTime = New DateTime(dtNow.Year, dtNow.Month, dtNow.Day, hc, mc, 0)

If dtCandidate < dtNow Then
    dtCandidate.AddDays(1)
End If

execTime = dtCandidate.Subtract(dtNow)
t = New Timer(tcb,Nothing,execTime,TimeSpan.Zero)

Then you just need a Sub to do your task:

Public Sub DoStuff(obj As Object)
'...Do Some Kind of Work
End Sub