myVariable = 9;
console.log(myVariable); // 9
function hello() {
// applicable only for this function
'use strict';
string = 'hello'; // throws an error
}
hello();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: strict mode code can sometimes be made to run faster than
identical code that's not strict mode.
-Prohibits some syntax likely to be defined in future versions of ECMAScript.// Non-strict code...
(function(){
"use strict";
// Define your library strictly...
})();
// Non-strict code... // File: myscript.js
'use strict';
var a = 2;
....function doSomething() {
'use strict';
...
}