Progress bar image and Message

Hi

I have a video upload page.

When user clicks on submit button : I want to disable that button and display progress bar image and show label "Please wait. Upload In Progress..." 
I am using html button and made it runat="server".I am able to disable button using :
btnUpload.Attributes.Add("onClick", "this.disabled=true");

But after disabling button I am not able to display hidden image and label.

Since both image and label are hidden , when I try to make them visible in javascript I get error of null object because of hidden controls.  

I tried to set width height = 0 and then changed width and height. , which worked in mozilla But in I ...