Hi, I was wondering if there is some built in way of disabling a submit button after it has been clicked.
And, if there is no default way, how should I do this.

I found something like this to put in DisableSubmit.js:

function DisableButton() {
    document.forms[0].submit();
    window.setTimeout("disableButton('" + window.event.srcElement.id + "')", 0);
}

function disableButton(buttonID) {
    document.getElementById(buttonID).disabled=true;
}

And then this in the page load:

btnSo.Attributes.Add("onclick", "DisableButton()")

And I thought of something like in the page init:

Dim objCSS As Control = Me.Page.FindControl("CSS")
If Not objCSS Is Nothing Then
    Dim objScript As New HtmlGenericControl("script")
    objScript.Attributes("language") = "javascript"
    objScript.Attributes("type") = "text/javascript"
    objScript.Attributes("src") = "/desktopmodules/[MODULENAME]/DisableSubmit.js"
    objCSS.Controls.AddAt(0, objScript)
End If

But it doesn't seem to work...

Noting is built into the ClientAPI to stop a double post.  What you have posted seems like it would work, yet you said it didn't.  Did you get an error?   Do you have a url to review?

[edit]

For applications I work on that I wish to stop a double post, I usually use server-side logic and session state.  The idea is simple.  Every page that renders pushes down the current date in a hidden field  (you could use the ClientAPI for this, by RegisterClientVariable).  On every postback, I check the posted value against what is currently in session state as the lastposedvalue.  If session timestamp less-than posted, allow it through.  when done, assign timestamp to session. 

Thanks a lot Jon, and especially Vitkoz, very nice solution.

Wouldn't it be a great idea to build a code library with usefull scripts (like this) for DNN somewhere on the site?