Is javascript a statically typed or a dynamically typed language?

 JavaScript is a dynamically typed language. In a dynamically typed language, the type of a variable is checked during run-time in contrast to statically typed language, where the type of a variable is checked during compile-time.

Since javascript is a loosely(dynamically) typed language, variables in JS are not associated with any type. A variable can hold the value of any data type.
For example, a variable which is assigned a number type can be converted to a string type:

var a = 23;
var a = "Hello World!";