Javascript behaviour difference between IE and Mozilla Firefox?
I have the following code which should update a label to say "please wait..", then run a function, and then update the label again to say it has completed:

    <asp:Button ID="Button1" runat="server" Text="Upload"
                        onclientclick="document.getElementById('errorMessage').innerText='Please Wait...';" 
                        onclick="Button1_Click"  />

This works fine in IE, but not in Firefox. 

When I run it in Firefox the label does not change until the process completes.

Is there a way to force the javascript to update the page before running the C# function?
Javascript behaviour difference between IE and Mozilla Firefox?
===

I have the following code which should update a label to say "please wait..", then run a function, and then update the label again to say it has completed:

    <asp:Button ID="Button1" runat="server" Text="Upload"
                        onclientclick="document.getElementById('errorMessage').innerText='Please Wait...';" 
                        onclick="Button1_Click"  />

This works fine in IE, but not in Firefox. 

When I run it in Firefox the label does not change until the process completes.

Is there a way to force the javascript to update the page before running the C# function?