1//statement
2A statement is an instruction to perform a specific action. Such actions include creating a variable or a function, looping through an array of elements, evaluating code based on a specific condition etc. JavaScript programs are actually a sequence of statements.
3//expression
4Any unit of code that can be evaluated to a value is an expression. Since expressions produce values, they can appear anywhere in a program where JavaScript expects a value such as the arguments of a function invocation.