basics
BLOCK The phone store employee must go through a series of steps to complete the checkout as you buy your new phone. Similarly, in code we often need to group a series of statements together, which we often call a block. In JavaScript, a block is defined by wrapping one or more statements inside a curlybrace pair { .. } . Consider: var amount = 99.99; // a general block { amount = amount * 2; console.log( amount ); // 199.98 } This kind of standalone { .. } general block is valid, but isn't as commonly seen in JS programs. Typically, blocks are attached to some other control statement, such as an if statement (see "Conditionals") or a loop (see "Loops"). For example: var amount = 99.99; // is amount big enough? if (amount > 10) { // <-- block attached to `if` amount = amount * 2; console.log( amount ); // 199.98 } We'll explain if statements in the next section, but as you can see, the { .. } block with its two statements is att...