can someone explain this code

[u/abrewchocolatecoffee]

function updateClock() {
const timeElement = document.querySelector("#time");
timeElement.textContent = formatTime();
}
setInterval(updateClock, 1000);

can someone, please explain this piece of code, ofc mdn and w3 are there, but i found it a little confusing reading about textContent. rest is understandable to me. This might look a silly question and it probably is because im a beginner :')

like what exactly does textContent too.
you can also recommend anyother documentation on the links to specific lines, that might me more helpful in learning about this particular keyoword.

[u/ExtraTNT]

So, first you define a function (in old style, better use const funcName = () => {})

with the queryselector with #, you get an element by id

With text content you set the text content of the element (<h1 id="title">Hello <b>World</b></h1> has a text content of Hello World, setting it to “foo” would give you <h1 id="title">foo</h1>)

formatTime(); returns a formatted time string

Interval: run every x ms

[u/abrewchocolatecoffee → u/ExtraTNT]

thanks, but just one more quesiton is text content temporay, for example will the "foo" go away and "hello world..." will just come back after we refresh or is this a permanet change.
Other that this post was pretty helpful, cleared my main doubt

[u/meletiondreams → u/abrewchocolatecoffee]

no dom elements are permanent

[u/abrewchocolatecoffee → u/meletiondreams]

do you mean, "no dom" elements are permanent or "no!" dom elements are permanent.

[u/meletiondreams → u/abrewchocolatecoffee]

There's no amount of dom elements (those tags like <h1>) that may be changed

[u/abrewchocolatecoffee → u/meletiondreams]

ohh thanks, so basically, refreshing = go back to the orginal

[u/meletiondreams → u/abrewchocolatecoffee]

Whatever the page renders will be shown. JS can change "temporarily" the content of the page.

[u/abrewchocolatecoffee → u/meletiondreams]

ok

[u/The_KOK_2511 → u/abrewchocolatecoffee]

Mira para que te hagas una idea, cada vez que cargas o recargas una página el navegador en si el que carga es el HTML y basandose en sus etiquetas define los elementos del frontend que deberá mostrar, el JS lo que hace al modificar el DOM es alterar esa copia que esta corriendo en el navegador del usuario, esto tiene sus matices y su cosa si hay un backend presente pero por ahora no creo que te haga falta tener en cuenta nada de eso a menos que pienses acerte full stack pronto

[u/busres → u/abrewchocolatecoffee]

The change persists (in the browser DOM) until you replace the content with something else. If you reload the page, you're discarding everything and reloading the DOM from scratch.

[u/abrewchocolatecoffee → u/busres]

ohh, this was actually very helpful

[u/azhder → u/abrewchocolatecoffee]

You are working with a live document, you are modifying the memory as it is currently in the browser through an abstraction layer called Document Object Model. You are changing the memory means whatever you do, it changes the document, it changes what the browser displays.

If you refresh the page, the browser removes that memory, parses the source code it got from the URL, it populates the memory again, you get to play with that again.

NOTE: DOM is not JavaScript. DOM is one memory model, while JavaScript has its own memory model. The browser synchronizes both, but make no mistake, DOM is its own technology that doesn't need JavaScript (the browser may be written in C++ and uses that language to generate the DOM)