Declaring an HTML ID not necessary in Javascript - The questions

[FrankieGTH]

Hi,

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?

[dsonesuk]

IF the id value is myHeader then
myHeader.innerHTML = "Have a nice day!";
Will work as that is dot notation which has been about for a whille now!

[justsomeguy]

There's an article here if you want more information:

https://www.tjvantoll.com/2012/07/19/dom-element-references-as-global-variables/

[davej]

Although it works -- as a part of browser backward-compatibility -- I doubt that anyone recommends that approach anymore.

[justsomeguy]

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>
</div>

 

[FrankieGTH]

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.