I am trying to understand the short entry on IDL in the MDN Glossary.
In particular, I am struggling with the behavior described in the 4th paragraph under the “Content versus IDL attributes” header.
Most of the time, IDL attributes will return their values as they are really used. For example, the default type for
<input>elements is"text", so if you setinput.type="foobar", the<input>element will be of type text (in the appearance and the behavior) but the"type"content attribute’s value will be"foobar". However, the type IDL attribute will return the string"text".
I will list a series of questions, along with my current ‘informed guesses’ in bulletpoints. I would like to either confirm my understanding, or expose my lack of it. Any input, clarification, or critique is appreciated (the questions may be fully off-base).
What does ‘their values as they are really used’ mean in this context (their default value [e.g, "text"], or the value set in a specific context [e.g, "foobar"])?
- default (in the example,
"test") – hence the final sentence of the quote.
Is the <input> element’s type an IDL or content attribute?
- (technically both? but inasmuch as we access it through
input.typeit is an) IDL attribute
If IDL attributes are set using element.foo, doesn’t input.type qualify as setting an IDL attribute (in which case the "type" content attribute should not be "foobar")?
- This misses a key behavior of IDL attributes w.r.t. content attributes: content atttributes can be set through IDL attributes, while leaving the IDL attribute itself unchanged (as hinted in the middle of this answer).