Question

I have to resolve a problem in some code assigned to me and the problem is that following this code in page.init else statemant:

Me.SaveChangesButton.Attributes.Add("OnClick", 
    "if (!confirm('Are you sure?')){
        return false;
     } else {
        document.getElementById('SaveChangesButton').disabled = true; 
        document.getElementById('rejectButton').disabled = true;
     }
")

overrides this code:

Protected Sub SaveChangesButton_Click(ByVal sender As Object, ByVal e As 
System.EventArgs) Handles SaveChangesButton.Click

Question [edited]

1. How can I bind confirm() to button so that it doesn’t override my handler function?
2. Where in the code would it be best practice to bind it?
3. If I remove second part else {document.getElementById('SaveChangesButton').disabled =
true; document.getElementById('rejectButton').disabled = true;} it works correctly, but how should I write it so it continues to execute SaveChangesButton_Click, as I understand only the second part overrides handler?
4. How can I execute those two lines document.getElementById('SaveChangesButton').disabled = true;
document.getElementById('rejectButton').disabled = true; and still execute SaveChangesButton_Click handler without overriding it?

Answer 1

1) You should use OnClientClick:

Me.SaveChangesButton.OnClientClick = @"
    if (!confirm('Are you sure?')) {
        return false;
    } else {
        document.getElementById('SaveChangesButton').disabled = true; 
        document.getElementById('rejectButton').disabled = true;
    }"

2) If you bind the SaveChangesButton_Click in the Page.Init, I would then set the OnClientClick too.

3,4) The OnClientClick fires (sort of) before the server side OnClick (of course). This makes you disabling your button, before firing the OnClick. And OnClick won’t fire on a disabled button. What to do? Delay disabling your button.

Me.SaveChangesButton.OnClientClick = @"
if (!confirm('Are you sure?')) {
    return false;
} else {
    setTimeout(function(){
        document.getElementById('SaveChangesButton').disabled = true; 
        document.getElementById('rejectButton').disabled = true;
    }, 100);
}"

And this actually makes your question a duplicate of this one…