Comments are how developers let it be known what script does what. Not just to other people, but to themselves as well. Picking up Monday what you left off on Friday can be bewildering even to seasoned pros. Lets take a look some code courtesy of ibm.com/design. A few things to note:
There are two ways to denote comments; /* for multi-line comments and // for single line comments.
*Var, which stands for variable.
*Const, which denotes a constant, meaning the value is not fluid.
*Let, which has a fluid value.
Variables are expressed with and equal sign like so:
let x = 4;
Semicolons express the end to a statement. It means that that is the end of that expression. To keep files easy to read developers then go on to the next line, but that is not an absolute necessity. Forgetting to enter a semicolon will cause an error in your code.