Hi,
> ...because I
> know javascript is prone to memory leaks...
Javascript is not prone to memory leaks. Some *browsers* are prone to
memory leaks, particularly where Javascript and the DOM interact (IE
especially), but that's nothing to do with Javascript itself. Not to
be picky or anything. ;-)
> ...I'm wondering if there is a better way of doing this...
Looks mostly fine to me. I think I'd probably solve the problem
differently (even delegation, most likely), but that doesn't mean your
solution is worse than mine would be. Some notes FWIW:
1. In a couple of places you're duplicating work, searching the DOM
again for something you already have (such as when unhooking the old
handler and hooking the new one)
2. It seems a bit odd that secondFunction is inside firstFunction, but
it's not a big deal.
3. The code is basically duplicated between the two functions;
recommend abstracting and parameterizing
4. You haven't shown where you first set up firstFunction, but I'm
guessing it has further duplication, looking something like this:
$$("input[value='height toggle']")
[0].observe('click',firstFunction);
Without fundamentally changing how you're doing it or affecting your
markup, I'd refactor it like this:
* * * *
functon setupToggler() {
var height;
$$("input[value='height toggle']")[0].observe('click', handler);
function handler(event) {
height = height === "50px" ? "100px" : "50px";
$$("div.content").invoke("setStyle", {height: height});
}
}
* * * *
...where you set it up by calling setupToggler. The event handler
doesn't change, just what it does. The frist time the event fires,
`height` will be undefined, thus not === "50px", and so it gets set to
"50px". The second time, it's === "50px" and so it gets set to
"100px". The third time it's not === "50px" again. Etc.
The above assumes that your input with value='height toggle' is not
dynamic (e.g., you don't remove it and then add another one later).
(Your code sort of does as well, in that it won't release old one if
it changes.)
It may also be worth generalizing it.
FWIW,
--
T.J. Crowder
Independent Software Consultant
tj / crowder software / com
www.crowdersoftware.com
On May 14, 11:26 am, orbiter <dkarapet...@gmail.com> wrote:
> A quick question about event management. I have a button that toggles
> a style field on certain elements between two different values and
> here's the code that I use:
>
> function firstFunction(event) {
> $$("div[class='content']").invoke("setStyle",{height:"50px"});
> $$("input[value='height toggle']")[0].stopObserving('click');
> function secondFunction(event) {
> $$("div[class='content']").invoke("setStyle",{height:"100px"});
> $$("input[value='height toggle']")[0].stopObserving('click');
> $$("input[value='height toggle']")
> [0].observe('click',firstFunction);
> };
> $$("input[value='height toggle']")
> [0].observe('click',secondFunction);
>
> };
>
> Basically what I do is toggle between two function on the same button
> by having one set up the observer for the other by first clearing all
> the other observers, a lot like a mutually recursive set of functions
> and I'm wondering if there is a better way of doing this because I
> know javascript is prone to memory leaks and I'm trying to avoid them.
>
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