I still don't understand how it works...?

I posted a few days ago about how I don’t fully get the full concept of arguments in JavaScript. Like passing arguments in parameters, etc.

I was watching this tutorial and following along to it. I understand the code like what the code is supposed to do (open navbar in mobile screen) but, again, arguments? I just can’t get my head around it…

how does this code below work with the argument name element? I know it can be named whatever you would like but why does an argument have to be named for this function and querySelector??

How does this help in JavaScript?

//Select element function… so basicallly i will call this function, and whatever class or element or ID that I pass, it is going to be returned to me
const selectEl = function(element) {
return document.querySelector(element)
let menuToggler = selectEl(’.menu-toggle’);
let body = selectEl(‘body’);
menuToggler.addEventListener(‘click’, function (){

a function has parameters
they are variables that exist inside the function and can have any name

function myFunc (bananas) {
   // doing something with bananas

when you call a function you pass arguments in and these arguments are assigned to the parameters in order

myFunc("orange") // the bananas parameter in the function has now value of "orange"
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Let’s put aside javascript functions for now. Think about algebraic functions. let’s say you have a function f(x) and it is equal to 2x+1. The “x” is like the argument in javascript functions. By plugging in a number (let’s say “3” for example), you will get a value given by the function.

f(3) = 2(3) + 1
f(3) = 6+1
f(3) = 7

Now how does this relate to a javascript function?
I will create the same function as shown above in javascript:

function y_equals_two_x_plus_1(x){
return 2 * x + 1;

you don’t actually need that crazy long title. try logging the function to the console while plugging in different numbers.

console.log( y_equals_two_x_plus_1(3) );

the function will return the given number. The main usage of a function is so that you won’t need to write so much of the same code over and over again.

Hope that helps.

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Ok, so arguments are values or references that are handed from the calling function or object to the called function or object. The idea behind this is like you are handing a function some data that it will use.

For your example specifically, element is passed by a string value that contains either the classes, indexes, and tags that will be passed to a selector in order to get the DOM object.

Now, element is only a placeholder for the argument that are passed to the function, but in some languages and applications you can also use this placeholder as a tag (I am not sure if you can do this in JavaScript though).

For example: