8-point rule in JavaScript strict mode

Role

[1] The elimination of some of the JS syntax unreasonable, not rigorous, unsafe problems, reduce weird behavior and ensure that the code is safe to run

[2] Improve compiler efficiency, increase operating speed

Use

[1] The entire script is enabled in strict mode, at the top of the execution: "Use strict";

[2] Execution of strict mode in the specified function, the first line of the function body: "Use strict"

[3] browsers that do not support strict mode execute "use strict" as a string statement, and browsers that support strict mode will turn on strict mode

[4] A browser that supports strict mode includes ie10+, firefox4+, safari12+, opera12+, Chrome

Rules
"1" "Variable"
[A] does not allow accidental creation of global variables

"Use strict"= ' Hello world! ';

[B] cannot call the delete operator on a variable

"Use strict"; var color = ' red '; delete color;

"2" "Object"
[A] cannot assign a value to a read-only property

"Use strict"; var person = {    name:' Cook '};object.defineproperty (person,' name ', {     false  = ' Nicholas ';

[B] Cannot use the delete operation for a non-configurable property

"Use strict"; var person = {    name:' Cook '};object.defineproperty (person,' name ', {     false }); Delete person.name;

"3" function
[A] parameter must be unique

"Use strict"; function Sun (num,num) {    //TODO}

[b] Modifying the parameter is not reflected in the arguments

function Showvalue (value) {    = "Foo";    Alert (arguments[0]);     // non-strict mode: "Foo"    // Strict mode: "Hi" }showvalue ("Hi");

[C] not allowed to use Arguments.callee and Arguments.caller

"Use strict"; function fn (num) {    return  arguments.callee (num);} FN (2);

"Use strict"; function outer () {    inner ();} function inner () {    alert (Inner.caller ());} Outer ();

' 4 ' does not allow Eval () to create a variable or function in the containing context

"Use strict"; function fn () {    eval ("var x=10");    alert (x);} fn ();

// allow the following actions var result = eval ("var x = ten, y = 11; X+y "); alert (result); //  +

"5" does not allow eval and arguments as identifiers, nor is it allowed to read and write their values

"Use strict"; var eval = ten; var arguments = 20;

' 6 ' does not allow this value to be null or undefined

"Use strict"; var color = "Red"; function fn () {    alert (this. color);} fn ();

' 7 ' does not allow the WITH statement

"Use strict";  with (location) {    alert (href);}

' 8 ' does not allow the use of octal literals

"Use strict"; var value = 010;

8-point rule in JavaScript strict mode