What does “use strict” do in JavaScript, and what is the reasoning behind it?

Question

Recently, I ran some of my JavaScript code through Crockford\'s JSLint, and it gave the following error:

Problem at line 1 character 1: Missing \"use

Answer 1

Strict mode makes several changes to normal JavaScript semantics:

• eliminates some JavaScript silent errors by changing them to throw errors.

• fixes mistakes that make it difficult for JavaScript engines to perform optimizations.

• prohibits some syntax likely to be defined in future versions of ECMAScript.

for more information vistit Strict Mode- Javascript