Lets say I have a web app which has a page that may contain 4 script blocks - the script I write may be found in one of those blocks, but I do not know which one, that is handled by the controller.
I bind some onclick events to a button, but I find that they sometimes execute in an order I did not expect.
Is there a way to ensure order, or how have you handled this problem in the past?
If order is important you can create your own events and bind callbacks to fire when those events are triggered by other callbacks.
$('#mydiv').click(function(e) {
// maniplate #mydiv ...
$('#mydiv').trigger('mydiv-manipulated');
});
$('#mydiv').bind('mydiv-manipulated', function(e) {
// do more stuff now that #mydiv has been manipulated
return;
});
Something like that at least.
The order the bound callbacks are called in is managed by each jQuery object's event data. There aren't any functions (that I know of) that allow you to view and manipulate that data directly, you can only use bind() and unbind() (or any of the equivalent helper functions).
Dowski's method is best, you should modify the various bound callbacks to bind to an ordered sequence of custom events, with the "first" callback bound to the "real" event. That way, no matter in what order they are bound, the sequence will execute in the right way.
The only alternative I can see is something you really, really don't want to contemplate: if you know the binding syntax of the functions may have been bound before you, attempt to un-bind all of those functions and then re-bind them in the proper order yourself. That's just asking for trouble, because now you have duplicated code.
It would be cool if jQuery allowed you to simply change the order of the bound events in an object's event data, but without writing some code to hook into the jQuery core that doesn't seem possible. And there are probably implications of allowing this that I haven't thought of, so maybe it's an intentional omission.
function bindFirst(owner, event, handler) {
owner.unbind(event, handler);
owner.bind(event, handler);
var events = owner.data('events')[event];
events.unshift(events.pop());
owner.data('events')[event] = events;
}
You can try something like this:
/**
* Guarantee that a event handler allways be the last to execute
* @param owner The jquery object with any others events handlers $(selector)
* @param event The event descriptor like 'click'
* @param handler The event handler to be executed allways at the end.
**/
function bindAtTheEnd(owner,event,handler){
var aux=function(){owner.unbind(event,handler);owner.bind(event,handler);};
bindAtTheStart(owner,event,aux,true);
}
/**
* Bind a event handler at the start of all others events handlers.
* @param owner Jquery object with any others events handlers $(selector);
* @param event The event descriptor for example 'click';
* @param handler The event handler to bind at the start.
* @param one If the function only be executed once.
**/
function bindAtTheStart(owner,event,handler,one){
var eventos,index;
var handlers=new Array();
owner.unbind(event,handler);
eventos=owner.data("events")[event];
for(index=0;index<eventos.length;index+=1){
handlers[index]=eventos[index];
}
owner.unbind(event);
if(one){
owner.one(event,handler);
}
else{
owner.bind(event,handler);
}
for(index=0;index<handlers.length;index+=1){
owner.bind(event,ownerhandlers[index]);
}
}