In JavaScript conversion between different two build-in types called coercion.
Coercion comes in two forms in JavaScript: explicit and implicit.
Example of explicit coercion:
var a = "20";
var b = Number( a );
a; // "20"
b;
Example of implicit coercion:
var a = "20";
var b = a * 1; // "20" implicitly coerced to 20 here
a; // "20"
b; // 20 - the number