► The fifth edition of ECMAScript specification has introduced Script Mode.

► Strict Mode applies a layer of constraint on JavaScript.

► It throws errors for actions that are problematic and didn't throw an error before.

► It throws errors for the actions which are potentially unsafe.

► It shut downs the functions which are poorly thought out.

► Strict mode solves mistakes that are responsible for the difficulty of JavaScript engines to perform optimizations.

► To enable the strict mode we have to add the string literal "use strict" on the top of file or function as follow :

function myfunction()

{

"use strict";

var v = "I am a strict mode function";

}