use let when creating variables for the first time

use const to declare a constant (unlike all caps in ruby) - can't redefine/replace value of constant in JS

lowerCamelCase i.e. iPhone

increment a value:

let x = 5;
x++;
#x is now 6

Methods that accept code: in JavaScript, these are called “anonymous functions” rather than “blocks”.
If the method provides values for block variables, in Ruby we name them within optional “pipes” | | after the do. In JavaScript, we name them within the parentheses ( ) (which are not optional) after function.

JS comparisons use triple ===, not double ==.

Beware: There’s also a JS double == (non-strict equivalence) operator. In most cases, you should use ===.

jQuery() alias $() for shorthand

In JavaScript, you have to execute the function explicitly by adding the parentheses, even if there are no arguments. ie chi.text() not chi.text

Any CSS property/value pair can be set with the css() function.

Event handlers with on()

$("body").on("click", "#bye", function() {
  $(".west").slideToggle();
});

This is saying: “Within , find elements with an id of bye, and when they are clicked run the following callback.” Now, whenever the div is clicked, elements with class west will slide up and down.