Thank you, Mike. You're so patient and helpful!
Apparently I didn't understand insertAfter() well enough. I thought it
would move the object, not duplicate the object.
Is there a function in jQuery that simply moves an object? Or, if I
remove() the object, do I need to add() it again if I want to use it
some time later?
Again, thank you very much!
On Jan 3, 1:28 pm, "Michael Geary" <m...@mg.to> wrote:
> Do you notice that the page also blanks out when you get the error? Why is
> that?
>
> Try this:
>
> Open your page and open the Firebug panel.
>
> Now click the button that provokes the error. Then click on the filename in
> the Firebug error message (my.etc.js line 68). You should get the source
> code for your jQuery.ajax function.
>
> The error is happening in the beforeSend callback. Set a breakpoint on the
> line *before* the error, line 67, by clicking on the line number.
>
> Now click the Back button, then click the button that provokes the error
> again. It should stop on line 67.
>
> The page still looks OK.
>
> Click in the yellow "New watch expression" bar and type $ and the Enter key.
> You should get a function listed in the watch window, and if you expand it,
> it will be seen to be the jQuery constructor.
>
> Now step over the code in line 67. (On Windows, the F10 key will do it. Or
> on any platform, use the Step Over icon on the right side of the Firebug
> panel.)
>
> Boom. The page blanks out, and the $ in the watch window turns into a
> reference error.
>
> Clearly, the code on page 67 has trashed your document.
>
> Why?
>
> Well, the code in line 67 is:
>
> $('#respond').insertAfter($("div.comment"));
>
> That's taking an existing DOM element and inserting it in a second place in
> the DOM. This is a Very Bad Thing. A DOM node can't be in two places at
> once.
>
> Try repeating the experiment (you may need to restart Firefox first if it's
> badly trashed), and when you get to line 67, instead of stepping over it,
> enter either of these two statements in the Firebug console:
>
> $('#respond').remove().insertAfter($("div.comment"));
>
> Now you'll find that the document is not trashed; either statement executes
> successfully.
>
> This is because the statements avoid having the same node appear in two
> places. The first one removes the node from its current location before
> inserting it; the second one clones the node.
>
> I'm not sure which of these is what you want (if indeed either is), but this
> should help point you toward a solution.
>
> Note that the second version of the code:
>
> $('#respond').clone().insertAfter($("div.comment"));
>
> leaves the document in a somewhat invalid state, because there are now two
> elements with the same ID (respond). But that's not a document-trashing
> error. It's not recommended, but browsers generally let you get away with
> it.
>
> -Mike
>
>
>
> > From: Betty
>
> > I get this error in the Firefox error console: "$ is not defined".
> > it points me to line
> > $("div#respond>h3").html("Reply to");
>
> > I'm sure I've set jQuery properly because it works fine in
> > other browsers and the other jQuery effects I use can work in
> > Firefox. Only this part does not work. Actually, it works on
> > my local test computer, but if I upload the same file to the
> > server, this part gets this error. I can't understand why.
>
> > If you need an example, it's <a href="http://myfairland.net/mizong/
> > #comments">http://myfairland.net/mizong/#comments</a>. The
> > site is in Chinese. If you put the mouse on the comment part
> > and click the button that appears, with the Chinese word that
> > means "reply", you can get the error in Firefox.
>
> > This error really frustrates me. If you can help me, I'll
> > appreciate you very much! Many thanks!
