adding javascript window.confirm to linkbutton

[darrel]

Is it possible to pre-empt the javascript function used to do a postback
from a linkbutton?

I'd like to use linkbutton to delete a record and want to add a confirmation
box via javascript "are you sure you want to delete this record?" before it
executes the postback. The javascript is straightforward for this, but have
no idea how to have that intercept the post-back script.

-Darrel

 

[Mark Rae [MVP]]

Is it possible to pre-empt the javascript function used to do a postback
from a linkbutton?

I'd like to use linkbutton to delete a record and want to add a
confirmation box via javascript "are you sure you want to delete this
record?" before it executes the postback. The javascript is
straightforward for this, but have no idea how to have that intercept the
post-back script.

Any JavaScript function which returns false will intercept a postback e.g.

<asp:Button ID="MyButton" runat="server" OnClick="MyButton_Click"
OnClientClick="return confirm('Are you sure you want to delete this
record?');" Text="Delete" />

In the above example, when a user clicks on the Delete button, they will be
prompted with a client-side Yes/No alert - if they click Yes, the postback
will happen and run the code in the server-side MyButton_Click method - if
they click No, the postback will be intercepted and nothing further will
happen...

 

[darrel]

<asp:Button ID="MyButton" runat="server" OnClick="MyButton_Click"

OnClientClick="return confirm('Are you sure you want to delete this
record?');" Text="Delete" />

Slick, but can this be done with a linkButton? I don't see an OnClientClick
property for that.

-Darrel

 

[Mark Rae [MVP]]

Slick, but can this be done with a linkButton? I don't see an
OnClientClick property for that.

Yep - in the Page_Load, add the following code:

MyLinkButton.Attributes.Add("onclick", "return confirm('Are you sure you
want to delete this record?');");

 

[darrel]

MyLinkButton.Attributes.Add("onclick", "return confirm('Are you sure you

want to delete this record?');");

Hmm...I've done that, but the event handler still executes for the
linkButton regardless of whether I click OK or CANCEL in the confirmation
window.

-Darrel

 

[Mark Rae [MVP]]

Hmm...I've done that, but the event handler still executes for the
linkButton regardless of whether I click OK or CANCEL in the confirmation
window.

Actually, having just tried this, <asp:LinkButton> most certainly *does*
have an OnClientClick property:
http://msdn2.microsoft.com/en-us/li...controls.linkbutton.onclientclick(vs.80).aspx

 

[Collin Chung]

Actually, having just tried this, <asp:LinkButton> most certainly *does*
have an OnClientClick property:http://msdn2.microsoft.com/en-us/library/system.web.ui.webcontrols.li...

Hi guys, maybe Darrel is not using asp.net version 2.0, the msdn link
above says the onclientclick property is new for .Net framework
version 2.0 upwards. Anyway, to achieve the same effect using
javascript:

<script>
var mybutton = document.getElementById('linkButton1');
var oldonclickfunction = mybutton.onclick; //old postback method
mybutton.onclick=function() {
if(confirm('Are you sure you want to delete this record?'))
{oldonclickfunction();}
else{ return false;}
}
</script>

just need to replace linkButton1 with the button's id (extra caution
to make sure it's the control's unique hierarchically qualified id,
should be fine if the button is just on the form and not encapsulated
in a panel, table, grid or user control).

 

[darrel]

Hi guys, maybe Darrel is not using asp.net version 2.0

Yes, apologies for not clarifying that.

This is still a 1.1 app we're maintaining.

2.0 is moving along with MOSS, but for now, we're still going to be doing a
chunk of 1.1 work.

Anyway, to achieve the same effect using
javascript:

<script>
var mybutton = document.getElementById('linkButton1');
var oldonclickfunction = mybutton.onclick; //old postback method
mybutton.onclick=function() {
if(confirm('Are you sure you want to delete this record?'))
{oldonclickfunction();}
else{ return false;}
}
</script>

just need to replace linkButton1 with the button's id (extra caution
to make sure it's the control's unique hierarchically qualified id,
should be fine if the button is just on the form and not encapsulated
in a panel, table, grid or user control).

Collin:

Don't I still need to apply some sort of onClick event to the linkButton,
though? I'm not sure how the above script would know to intercept the
onClick event if there's nothing to trigger it.

-Darrel

 

[Mark Rae [MVP]]

Don't I still need to apply some sort of onClick event to the linkButton,
though? I'm not sure how the above script would know to intercept the
onClick event if there's nothing to trigger it.

MyLinkButton.Attributes.Add("onclick", "return confirm('Are you sure you
want to delete this record?');");

 

[darrel]

MyLinkButton.Attributes.Add("onclick", "return confirm('Are you sure you
want to delete this record?');");

Well, this is where my lack of Javascript skills begins to show. ;0)

Here's the function I'm using curtesy of Collin:

var mybutton = document.getElementById('lnkBtn_delete');
var oldonclickfunction = mybutton.onclick; //old postback method
mybutton.onclick=function() {
if(confirm('Are you sure you want to delete this record?'))
{oldonclickfunction();}
else{ return false;}
}

Right now, that's giving me a 'mybutton has no properties' javascript error.

Mark, your onclick event makes sense, but that same confirm is also
executing in the script of collins, so it appears that I'm going to cause
double-alerts in this case (provided I can get the 'mybutton has no
properties' error fixed...)

-Darrel

 

[Mark Rae [MVP]]

Well, this is where my lack of Javascript skills begins to show. ;0)

Here's the function I'm using curtesy of Collin:
Mark, your onclick event makes sense,

You can't have both...

 

[Andrew Morton]

Well, this is where my lack of Javascript skills begins to show. ;0)

Here's the function I'm using curtesy of Collin:

var mybutton = document.getElementById('lnkBtn_delete');
var oldonclickfunction = mybutton.onclick; //old postback method

Isn't JavaScript case-sensitive, so onclick should be onClick?

Andrew

 

[darrel]

Here's the function I'm using curtesy of Collin:

You can't have both...

Right. But that's kind of going back to my original problem...adding the
confirmation on the OnClick event of the linkbutton does NOT intercept the
postback. Regardless of whether or not I click OK or CANCEL, the postback is
still executed.

-Darrel

 

[darrel]

Isn't JavaScript case-sensitive, so onclick should be onClick?

'doh! yea, good catch!

That said, I still get the 'mybutton has no properties' error.

-Darrel

 

[Mark Rae [MVP]]

Right. But that's kind of going back to my original problem...adding the
confirmation on the OnClick event of the linkbutton does NOT intercept the
postback. Regardless of whether or not I click OK or CANCEL, the postback
is still executed.

It's working perfectly for me, although I am of course using ASP.NET v2. I
don't recall there being any problems in v1.x, though... Here's the code I'm
using:

<asp:LinkButton ID="lnkButton" runat="server" OnClick="lnkButton_Click"
OnClientClick="return confirm('Are you sure you want to delete this
record?');" Text="Delete" />

protected void lnkButton_Click(object sender, EventArgs e)
{
string strTest = String.Empty;
}

 

[darrel]

It's working perfectly for me, although I am of course using ASP.NET v2. I

don't recall there being any problems in v1.x, though... Here's the code
I'm using:

<asp:LinkButton ID="lnkButton" runat="server" OnClick="lnkButton_Click"
OnClientClick="return confirm('Are you sure you want to delete this
record?');" Text="Delete" />

Seems like 2.0 has a more intuitive 'OnClientClick' event.

If I apply the confirmation to the OnClick event in 1.1, the alert box
works...it just doesn't stop the postback from executing.

-Darrel

 

[Mark Rae [MVP]]

Seems like 2.0 has a more intuitive 'OnClientClick' event.

If I apply the confirmation to the OnClick event in 1.1, the alert box
works...it just doesn't stop the postback from executing.

Fair enough - unfortunately, I can't confirm this as I retired my one
remaining v1.1 installation quite a few months ago...

 

[darrel]

Fair enough - unfortunately, I can't confirm this as I retired my one
remaining v1.1 installation quite a few months ago...

I don't blame you. ;o)

-Darrel

 

[darrel]

If I apply the confirmation to the OnClick event in 1.1, the alert box

works...it just doesn't stop the postback from executing.

....CUASE I'M AN IDIOT!

doh'...finally realized it wasn't working because I forgot to put the RETURN
in there before the confirm command.

Sorry...USER ERROR!

Thanks for all the help Mark and Collin!

-Darrel

 

[Vijay Kumar]

Can you send the Full Code ( Client Side and Server Side Code )

Is it possible to pre-empt the javascript function used to do a postback
from a linkbutton?

I'd like to use linkbutton to delete a record and want to add a confirmation
box via javascript "are you sure you want to delete this record?" before it
executes the postback. The javascript is straightforward for this, but have
no idea how to have that intercept the post-back script.

-Darrel

On Thursday, August 02, 2007 5:45 PM Mark Rae [MVP] wrote:


Any JavaScript function which returns false will intercept a postback e.g.

<asp:Button ID="MyButton" runat="server" OnClick="MyButton_Click"
OnClientClick="return confirm('Are you sure you want to delete this
record?');" Text="Delete" />

In the above example, when a user clicks on the Delete button, they will be
prompted with a client-side Yes/No alert - if they click Yes, the postback
will happen and run the code in the server-side MyButton_Click method - if
they click No, the postback will be intercepted and nothing further will
happen...