Clarify v-model in the docs

[yamsellem]

What problem does this feature solve?

On multiple occasions, the docs clearly stated that v-model on a component uses value as the prop and input as the event (here and there).

On standards inputs, the documentation (here) don't explain what can be expected from v-model, and how to replace its default behavior (when writting wrappers, for example). I have found that:

• on input[type=text] and textarea, v-model uses value as the prop and input as the event
• on input[type=radio] and input[type=checkbox], v-model uses checked as the prop and input as the event — but seems to collide with value (#8379)
• on select, v-model uses value as the prop and change as the event

Some issues are related to this:

• dynamic input value with radio buttons don't work in IE11 #8379 — related to this section of the docs which breaks the default IE9+ compatibility
• <select @input="..."> doesn't work in IE11 but works with v-model #4701

May you please consider detailing for each control (input, radio, checkbox, select, textarea) what is the expected behaviour of v-model? This would be of great help!

What does the proposed API look like?

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Related to #9370

[phanan]

@yamsellem Thanks for reporting the issue. I see that it's almost an exact copy from vuejs/vue#9370, which has been explained/clarified by @yyx990803. Do you think his clarification doesn't answer your question?

[yamsellem]

@phanan I think @yanxyz clarification is:

• the issue is not related to vue but to its docs: I copied it here
• the issue is not related to component but to standard inputs: I've tried to clarify the point here

In a nutshell: the expected behavior of v-model is not documented for standard inputs, and it would be of great help if it was.

(so no, @yyx990803 don't answer my question, sorry)