JS Summary three ...

1. Operators: Add, subtract, multiply, divide, and seek redundancy.

var total = (1 + 4);

var i = 100;

var temp = (i-20)/2;

Alert ("ten" +)//return1020;

Alert (ten +)//return30;

2. Post Increment/decrement operator: + +/--

var i = 10;

var a = i++; i = i + 1;

alert (a); A = 10;

var a = ++i; i = i + 1;

alert (a); A = 11;

Tip: Execute from left to right, if a = i++, then A is first equal to I, then I is added;

If a = ++i, then the ++i is executed first and then assigned to a.

3. Comparison operators:>, <, =, >= <=, = =, = =,! =,!===

Alert (> 5); Outputs true;

var i = 100;

var n = 100;

alert (i = = n); outputs true;

Alert (i! = n); outputs false;

alert (i = = N)//data type and value all want to wait.

4. Logical operators:&&, | |,!

&&: Logic and;

|| : Logical OR;

！ : logical non;

var i = 8;

Alert (I < 5 && i < ten); output false;

Alert (i > | | i <); output true;

Alert (! ( 10>5)); Outputs false;

5. Program Flow control:

A. Conditional statement if:

if (> 5) {

Alert ("Hello World");

}

var i = 90;

if (i > 100) {

Alert (i + "greater than 100");

}else if (i > 80) {

Alert (i + "greater than 80");

}else {

Alert (i + "less than 100");

}

B.switch statement:

var a = B;

Switch (a) {

Case "A":

Alert ("You have selected a");

Break

Case "B":

Alert ("You have selected B"); Carried out this.

Break

Case "C":

Alert ("You have selected C");

Break

Default

Alert ("Welcome to the next time!") ");

}

JS Summary three ...