Mention avoid binding to HTML global properties

[ebidel]

http://www.w3.org/html/wg/drafts/html/master/dom.html#global-attributes

.style for example, presents all kinds of problems.

[sjmiles]

I think this is a misunderstanding. There is no problem binding to HTML global attributes that I'm aware of.

The known problem area is with overriding native properties. So, if you put title: 'foo' in your prototype, this is an override of the C++ bound title property and weird things can happen. The correct way to initialize this native property would be to put this.title = 'foo' in the ready method.

[ebidel]

It's possible I misunderstood @sorvell.

What about the case where the published property is a native property and you want to initialize it via attribute data binding e.g. <my-element title="{{someTitle}}">? Will the world blow up?

[sorvell]

No, that should work just fine. The issue is only doing what Scott
mentioned above:

Problem:

Polymer.register(this, {
title: 'foo'
});

On Fri, Jun 21, 2013 at 4:30 PM, Eric Bidelman notifications@github.comwrote:

It's possible I misunderstood @sorvell https://github.com/sorvell.

What about the case where the published property is a native property and
you want to initialize it via attribute data binding e.g. ? Will the world blow up?

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/90#issuecomment-19846168
.

[ebidel]

There's a lot of subtly here. How about style? The output of the following is Hello World! [object CSSStyleDeclaration], even though I set this.style in ready(). If certain properties can't be overridden, we need to mention that.

http://jsbin.com/ofoqah/3/edit

<element name="my-element" attributes="style">
  <template><content>Hello World! {{style}}</content></template>
  <script>
    Polymer.register(this, {
      ready: function() { this.style = "foo"; }});
  </script>
</element>

Most people are going to try something similar to this and scratch their head for eternity.

[sjmiles]

style is a property of Element, it's an object of type CSSStyleDeclaration. element.style="foo" makes no sense in any context.

We have an ticket which involves throwing a warning if you attempt to override a native property (which, btw, you should totally be able to do except for for historical browser nasties).

If you think users will find this confusing, I think it means we need a better way of talking about it, because the underlying conceptual model is simple and sane.

[ebidel]

The style example was contrived, but illustrates what people will try to do. I saw it twice in one day.

Warnings will go a long way to help the head scratching. Properties won't be magically gobbled up into browser unknown. Do you have the ticket? To explain it, we have callout under publishing properties that points to source and the list of props that generate warnings.

[arthurevans]

Should have closed this a while back. There is an explicit caution in this section: http://www.polymer-project.org/docs/polymer/polymer.html#propertiesmethods (under the element prototype chain).