No problem. I read the texts you posted last time, so I think I now
know,
what "this" does :-)
This time I, of course, wanted to "this" to be the img to easily
change
the source.
On 18 Mai, 15:36, "T.J. Crowder" <[EMAIL PROTECTED]> wrote:
> > ..."this" will be the window object, not an instance of Songlist.
>
> Doh! Sorry, I forgot, it won't be window, it'll be the img element.
> I keep forgetting that Prototype's event hooking stuff will default
> 'this' in the handler to the element on which the event occurred. My
> bad, apologies.
> --
> T.J. Crowder
> tj / crowder software / com
>
> On May 18, 2:32 pm, "T.J. Crowder" <[EMAIL PROTECTED]> wrote:
>
> > Hi,
>
> > No, that code probably doesn't do what you mean it to do -- your code
> > hooking the event:
>
> > > img.observe('mouseover', Songlist.mouseover);
>
> > ...doesn't preserve "this" (as we discussed in another thread).
> > Consequently when this code gets called:
>
> > > mouseover: function() {
> > > this.src = 'anotherimage.gif';
> > > }
>
> > ..."this" will be the window object, not an instance of Songlist.
>
> > It's really worth stopping coding for a moment and reading up on how
> > "this" works in JavaScript. I've pointed you to this blog entry
> > before:http://blog.niftysnippets.org/2008/04/you-must-remember-this.html
>
> > Additionally, Flanagan's book will pay you back in time savings pretty
> > much any time you spend reading
> > it:http://www.oreilly.com/catalog/jscript5/http://www.amazon.com/dp/0596...
>
> > In terms of the actual problem with the above code, as with last time,
> > you want to use
> > bindAsEventListener:http://www.prototypejs.org/api/function/bindAsEventListener
>
> > Hope this helps,
> > --
> > T.J. Crowder
> > tj / crowder software / com
> > On May 18, 12:31 pm, "[EMAIL PROTECTED]"
>
> > <[EMAIL PROTECTED]> wrote:
> > > OK, I really tried hard before I posted the above message, but sitting
> > > on the toilet I found the mistake.
> > > The code must look like that, than it works:
>
> > > var Songlist = {
> > > initialize: function() {
> > > img = document.createElement('img');
> > > [...]
> > > img.observe('mouseover', Songlist.mouseover);
> > > $('body').insert(img);
> > > }
> > > mouseover: function() {
> > > this.src = 'anotherimage.gif';
> > > }
>
> > > }
>
> > > Songlist.initialize();
>
> > > On 18 Mai, 13:25, "[EMAIL PROTECTED]"
>
> > > <[EMAIL PROTECTED]> wrote:
> > > > Hello,
>
> > > > I habe a problem with the following code (shortened):
>
> > > > var Songlist = {
> > > > initialize: function() {
> > > > img = document.createElement('img');
> > > > [...]
> > > > img.observe('mouseover', this.mouseover);
> > > > $('body').insert(img);
> > > > }
> > > > mouseover: function() {
> > > > this.src = 'anotherimage.gif';
> > > > }
>
> > > > }
>
> > > > Songlist.initialize();
>
> > > > Passing the image with my mouse I always get the error: "handler has
> > > > no properties"!
> > > > I would be happy if you gave me a tip, where what causes this error!
>
> > > > M. Hoffmann
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