1.0、参考
1.1、算数运算符
| 运算符 | 运算 | 说明 | 示例 |
|---|
+
| a + b
| 加法 | var x = 2;
var y = x + 3;
|
| 字符串连接 | var s = 'abc' + '123';
//s = 'abc123'
|
+a
| 取正 | var x = 2;
var y = +x;
|
-
| a - b
| 减法 | var x = 2;
var y = x - 3;
|
-a
| 取相反数 | var x = 2;
var y = -x;
|
*
| a * b
| 乘法 | var x = 2;
var y = x * 3;
|
**
| a ** b
| 密方 | var x = 2;
var y = x ** 3;
|
/
| a / b
| 除法 | var x = 2;
var y = x / 3;
|
%
| a % b
| 取余 | var x = 2;
var y = x % 3;
|
++
| a++
| 后自增 | var x = 2;
var y = x++;
|
++a
| 先自增 | var x = 2;
var y = ++x;
|
--
| a--
| 后自减 | var x = 2;
var y = x--;
|
--a
| 先自减 | var x = 2;
var y = --x;
|
1.2、位运算符
| 运算符 | 运算 | 说明 | 示例 |
|---|
&
| a & b
| 按位与 | var x = 2;
var y = x & 3;
|
|
| a | b
| 按位或 | var x = 2;
var y = x | 3;
|
^
| a ^ b
| 按位异或 | var x = 2;
var y = x ^ 3;
|
~
| ~ a
| 按位取反 | var x = 2;
var y = ~ x;
|
<<
| a << b
| 左移b位 | var x = 2;
x <<= 3;
|
>>
| a >> b
| 符号位不移动 | var x = 2;
x >>= 3;
|
>>>
| a >>> b
| 符号位也移动 | var x = 2;
x >>>= 3;
|
1.3、赋值运算符
| 运算符 | 运算 | 相当于 | 示例 |
|---|
=
| var a = VALUE
| | var x = 2;
let y = x + 3;
|
+=
| a += b
| a = a + b
| var x = 2;
x += 3;
|
-=
| a -= b
| a = a - b
| var x = 2;
x -= 3;
|
*=
| a *= b
| a = a * b
| var x = 2;
x *= 3;
|
**=
| a **= b
| a = a ** b
| var x = 2;
x **= 3;
|
/=
| a /= b
| a = a / b
| var x = 2;
x /= 3;
|
%=
| a %= b
| a = a % b
| var x = 2;
x %= 3;
|
<<=
| a <<= b
| a = a << b
| var x = 2;
x <<= 3;
|
>>=
| a >>= b
| a = a >> b
| var x = 2;
x >>= 3;
|
>>>=
| a >>>= b
| a = a >>> b
| var x = 2;
x >>>= 3;
|
1.4、关系运算符
| 运算符 | 运算 | 说明 | 示例 |
|---|
==
| a == b
| 只要值等于即可，不管类型是否相同 | 1 == true //true
0 == false //true
0 == '0' //true
|
===
| a === b
| 不仅值相等，类型也要相同 | 1 === true //false
0 === false //false
0 === '0' //false
|
!=
| a != b
| 只要值不等于即可 | 1 != true //false
0 != false //false
0 != '0' //false
|
!==
| a !== b
| 只要值和类型有一个不相等，就算不相等 | 1 !== true //true
0 !== false //true
0 !== '0' //true
|
<
| a < b
| 小于 | 1 < 2 //true
'0' < 1 //true
|
<=
| a <= b
| 小于或等于 | 2 <= 2 //true
'2' <= 2 //true
|
>
| a > b
| 大于 | 1 > 2 //false
'0' > 1 //false
|
>=
| a >= b
| 大于或等于 | 2 >= 2 //true
'2' >= 2 //true
|
1.5、逻辑运算符
| 运算符 | 运算 | 说明 | 示例 |
|---|
&&
| a && b
| 逻辑与 | null && true //null
undifined && true //undefined
0 && true //0
'' && true //''
|
||
| a || b
| 逻辑或 | null || console.log('xx') //xx
undefined || console.log('xx') //xx
0 || console.log('xx') //xx
'' || console.log('xx') //xx
false || console.log('xx') //xx
|
!
| !a
| 逻辑非 | !null && console.log('xx') //xx
!undefined && console.log('xx') //xx
!0 && console.log('xx') //xx
!'' && console.log('xx') //xx
!false && console.log('xx') //xx
|
1.6、条件运算符
语法：
condition ? expression1 : expression2
示例：
var event = window.event ? window.event : e
1.7、其他运算符
| 运算符 | 运算 | 说明 | 示例 |
|---|
| typeof | typeof a
| 计算类型，返回类型字符串 | typeof null //object
typeof undifined //undefined
typeof 0 //number
typeof '' //string
typeof true //boolean
typeof eval //function
typeof Object //function
typeof Array //function
typeof Boolean //function
typeof Number //function
|
| instanceof | a instanceof b
| 判断a是否是b的实例 | null instanceof Object //false
|
| void | void(a)
| 得到undefined | <a href="javascript:void(window.open('about:blank'))">open</a>
|
| new | new constructor()
| 创建对象 | var date = new Date();
|
| delete | delete(a)
| 删除变量或者对象的属性 | var x = 5;
delete x
|
| in | index in Array
attr in Object
| 判断给定的字符串是否为对象的属性 | 'PI' in Math && console.log(Math.PI)
|
