Sure. Basically apply allows you to declare the scope of the function
you're calling, instead of letting that scope resolve normally. With
any function, it will take on the scope of whatever encloses it. So if
you declare a function without it being enclosed, "this" will resolve
to "window" in almost all cases.
function myFunc(){ alert(this); }
myFunc(); // [object Window]
If your function is enclosed in an object, say:
var obj = { name: 'myObject', myFunc: function(){ alert
(this.name); } };
obj.myFunc(); // myObject
then "this" will take on the scope of the object which encloses it.
Using apply, you can manually declare the scope the function will
have.
var obj1 = { name: 'obj1', myFunc: function(){ alert(this.name); }};
var obj2 = { name: 'obj2' };
obj1.myFunc.apply(obj2, []); // obj2
So the first argument of apply sets the scope, which is basically a
fancy way of saying, tells it what to make "this" inside the function.
The second argument of apply is an array, in which you can pass
parameters. So:
function myFunc(param1, param2, param3){
alert(this + ' is equal to ' + (param1 + param2 + param3));
}
myFunc.apply(12, [2,4,6]); // alerts "12 is equal to 12"
I hope I answered your question, but I fear I may have just rambled at
you. :(
On Feb 25, 4:24 pm, Nic Hubbard <nnhubb...@gmail.com> wrote:
> Ha! That worked perfectly! Thanks, I really appreciate that, I was
> lost.
>
> So, could you explain, just so I know, what this did:
> defaults.onComplete.apply(obj, []); ?
>
> On Feb 25, 1:07 pm, Eric Garside <gars...@gmail.com> wrote:
>
> > The problem is you're losing scope when calling onComplete. Try using
> > the .apply method. Instead of:
>
> > defaults.onComplete();
>
> > try:
>
> > defaults.onComplete.apply(obj.get(0), []);
>
> > That should get "this" back to what you're expecting it to be. You
> > could also skip a step and call:
>
> > defaults.onComplete.apply(obj, []);
>
> > ---
>
> > onComplete: function(){ alert(this.attr('class')); }
>
> > I'm pretty sure that should work. IF not, let me know, and I'll play
> > around with it locally and actually test it out.
>
> > On Feb 25, 3:52 pm, Nic Hubbard <nnhubb...@gmail.com> wrote:
>
> > > I was meaning when trying to call $(this) in the following
> > > circumstance:
>
> > > $('a.matrixStatus').matrixStatus({
> > > urlSuffix: '?action=status_posting',
> > > onComplete: function() {alert('Callback worked'); alert($
> > > (this).attr('class'));}
> > > });
>
> > > When I am trying to pass things to the custom function, using $(this)
> > > does not work.
>
> > > On Feb 25, 12:28 pm, brian <bally.z...@gmail.com> wrote:
>
> > > > Something like this? (no pun intended)
>
> > > > obj.click(function() {
> > > > var self = $(this);
>
> > > > ...
>
> > > > defaults.onComplete(self);
>
> > > > On Wed, Feb 25, 2009 at 3:11 PM, Nic Hubbard <nnhubb...@gmail.com>
> > > > wrote:
>
> > > > > I have built a custom callback into my plugin, here is an example:
>
> > > > > $.fn.matrixStatus = function(options) {
> > > > > var defaults = {
> > > > > urlSuffix: '?action=live',
> > > > > onComplete: function() {}
> > > > > };
>
> > > > > var options = $.extend(defaults, options);
>
> > > > > return this.each(function() {
> > > > > var obj = $(this);
> > > > > var itemDesc = obj.attr('rel');
> > > > > var itemId = obj.attr('id');
> > > > > var itemHref = obj.attr('href');
> > > > > obj.click(function() {
> > > > > if (!itemDesc == '') {
> > > > > var question = confirm('Are you sure you want to
> > > > > change the status
> > > > > of "'+itemDesc+'"?');
> > > > > } else {
> > > > > var question = confirm('Are you sure you want to
> > > > > change the
> > > > > status?');
> > > > > }
> > > > > if (question) {
> > > > > $.ajax({
> > > > > type: 'POST',
> > > > > url: itemHref + defaults.urlSuffix
> > > > > });
>
> > > > > // Run our custom callback
> > > > > defaults.onComplete();
>
> > > > > }
> > > > > return false;
>
> > > > > });
>
> > > > > });
>
> > > > > };
>
> > > > > For some reason when I try to use that function for a custom callback,
> > > > > it won't allow me to get the jQuery object that the plugin is
> > > > > targeting, so using $(this) within the onComplete function doesn't
> > > > > work and give me errors. Any idea why this would be?
