jQuery.widget: type of `element` parameter of _on() should be Selector, not jQuery

[usmonster]

According to the jQuery docs:

If Selector is specified as the type of an argument, it accepts everything that the jQuery constructor accepts, eg. Strings, Elements, Lists of Elements.

And according to the code, that looks like exactly what the element argument should be documented as. (Note that a jQuery is also a Selector.)

Should I put in a pull request?

[scottgonzalez]

While the implementation does support Selector, the real intention is to pass a jQuery object. I'd prefer to keep the docs saying so as that's what we really want to support. It'd be pretty strange to use a selector string here as it wouldn't be scoped within the element. I'll wait for others to chime in though.

[usmonster]

@scottgonzalez I was inferring the intention from the comment in the code (jquery/jquery-ui@0872aac9), so sorry if I misinterpreted. It seems harmless to support the text selector, though.

[scottgonzalez]

The code was definitely written to support Selector, but I'm not sure why it was (there's no reference to a ticket or discussion in the commit or code) and I don't remember the discussion.

I wouldn't say it's harmless. It can certainly be confusing to see this._on( ".foo", { ... } ) which looks very much like element.on( ".foo", ... ) except that the former is conditionally delegated based on the handlers. It's just awkward to have two selectors in the call to _on().

Just to make sure we're totally clear: Selector is the correct thing based on the code and this was clearly intentional based on @jzaefferer's commit. I'm just questioning whether we actually want that.

[arschmitz]

The only use case i can think of for this is in a situation where you want to bind to something outside the widget itself for example in mobile a panel may want to listen for events on the page and so pass a selector like ".ui-page" however this is easily done regardless by passing $( ".ui-page" ) instead.

Just to be clear we do not pass a selector anywhere in mobile like this just the only use case i can think of which makes sense.

[jzaefferer]

The commit is from March 2011, where I was working on the Grid project. We have a few things in the widget factory that came out of that project. I don't remember why this was needed though either.

[scottgonzalez]

We've decided that we only want to officially support jQuery objects.