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Declaring an HTML ID not necessary in Javascript - The questions


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I had a function in which I forgot to declare the ID of an element that played an important role in it. But the function still worked, without any console error reports; I saw the omission only today.  At first  I almost didn't believe it, but the demo linked from https://www.w3schools.com/jsref/prop_html_id.asp confirmed it. If you change that function to

function displayResult() {
    myHeader.innerHTML = "Have a nice day!";

it works just as well. That raises a few questions:

  1. Since when is that?
  2. How about browser support?
  3. Does W3Schools mention that anywhere and if not, why not?
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That article has some good reasons why it's not the best idea to count on that.  A simple reason would be that you simply can't refer to some elements like that.  None of these will be available:

<div id="document">
  <span id="alert">We have moved:</span>
  <span id="location">New address</span>


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Thank you, gentleman. I guess the JS devs forgot to write me about this change. 😉

I'll keep declaring vars and constants, if it were only because the next web dev that has to work with my scribbles may be a junior one. Who may see undeclared items as globals, which would confuse them.

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