1.Assignment operators(分配操作)

Name Shorthand operator Meaning
Assignment x = y x = y
Addition assignment x += y x = x + y
Subtraction assignment x -= y x = x – y
Multiplication assignment x *= y x = x * y
Division assignment x /= y x = x / y
Remainder assignment x %= y x = x % y
Exponentiation assignment x **= y x = x ** y
Left shift assignment x <<= y x = x << y
Right shift assignment x >>= y x = x >> y
Unsigned right shift assignment x >>>= y x = x >>> y
Bitwise AND assignment x &= y x = x & y
Bitwise XOR assignment x ^= y x = x ^ y
Bitwise OR assignment x |= y x = x | y

2.Comparison operators(比较运算符)

Operator Description Examples returning true
Equal (==) Returns true if the operands are equal. 3 == var1 ; "3" == var1; 3 == '3'
Not equal (!=) Returns true if the operands are not equal. var1 != 4 var2 != "3"
Strict equal (===) Returns true if the operands are equal and of the same type. See also Object.is and sameness in JS. 3 === var1
Strict not equal (!==) Returns true if the operands are of the same type but not equal, or are of different type. var1 !== "3" ;3 !== '3'
Greater than (>) Returns true if the left operand is greater than the right operand. var2 > var1; "12" > 2
Greater than or equal (>=) Returns true if the left operand is greater than or equal to the right operand. var2 >= var1 var1 >= 3`
Less than (<) Returns true if the left operand is less than the right operand. var1 < var2 "2" < 12
Less than or equal (<=) Returns true if the left operand is less than or equal to the right operand. var1 <= var2 var2 <= 5

3.Arithmetic operators

Operator Description Example
Remainder (%) Binary operator. Returns the integer remainder of dividing the two operands. 12 % 5 returns 2.
Increment (++) Unary operator. Adds one to its operand. If used as a prefix operator (++x), returns the value of its operand after adding one; if used as a postfix operator (x++), returns the value of its operand before adding one. If x is 3, then ++x sets x to 4 and returns 4, whereas x++ returns 3 and, only then, sets x to 4.
Decrement (–) Unary operator. Subtracts one from its operand. The return value is analogous to that for the increment operator. If x is 3, then –x sets x to 2 and returns 2, whereas x– returns 3 and, only then, sets x to 2.
Unary negation (-) Unary operator. Returns the negation of its operand. If x is 3, then -x returns -3.
Unary plus (+) Unary operator. Attempts to convert the operand to a number, if it is not already. +“3” returns 3.+true returns 1.
Exponentiation operator (**) Calculates the base to the exponent power, that is, baseexponent 2 ** 3 returns 8.10 ** -1 returns 0.1.

4.Bitwise operators

Operator Usage Description
Bitwise AND a & b Returns a one in each bit position for which the corresponding bits of both operands are ones.
Bitwise OR a | b Returns a zero in each bit position for which the corresponding bits of both operands are zeros.
Bitwise XOR a ^ b Returns a zero in each bit position for which the corresponding bits are the same.
Bitwise NOT ~ a Inverts the bits of its operand.
Left shift a << b Shifts a in binary representation b bits to the left, shifting in zeros from the right.
Sign-propagating right shift a >> b Shifts a in binary representation b bits to the right, discarding bits shifted off.
Zero-fill right shift a >>> b Shifts a in binary representation b bits to the right, discarding bits shifted off, and shifting in zeros from the left.

5.Logical operators

Operator Usage Description
Logical AND (&&) expr1 && expr2 Returns expr1 if it can be converted to false; otherwise, returns expr2. Thus, when used with Boolean values, && returns true if both operands are true; otherwise, returns false.
Logical OR (||) expr1 || expr2 Returns expr1 if it can be converted to true; otherwise, returns expr2. Thus, when used with Boolean values,
Logical NOT (!) !expr Returns false if its single operand that can be converted to true; otherwise, returns true.

Unary operators

delete
typeof
void

<a href="javascript:void(0)">Click here to do nothing</a>
<a href="javascript:void(document.form.submit())">Click here to submit</a>

in
instanceof

参考:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Expressions_and_Operators