Introduction to the use of bitwise AND value assignment operators (& =) in Javascript _ basic knowledge

This article mainly introduces information about the bitwise AND value assignment operators (& amp;) in Javascript. If you need them, you can refer to the bitwise AND value assignment operators (& =) in Javascript ), set the bitwise "and" operation result for the variable value and expression value. Both variables and expressions are considered as 32-bit binary values, while general expressions are all decimal integers. In this case, you must first convert them to the corresponding binary values, and then add 0 to the forward to supplement the 32-bit values.

The Code is as follows:

Result & = [integer 2]
Equivalent
Result = result & [integer 2]

& Perform the bitwise "and" operation on each bit of two 32-bit expressions. If both bits are 1, the result is 1. Otherwise, the result is 0.

Bit 1	Bits 2	Bitwise AND
0	0	0
1	1	1
0	1	0
1	0	0

The following example shows how to use the & bitwise AND operator and the & = bitwise AND value assignment operator:

The Code is as follows:

// 9 the binary value is 1001, and the 32-bit complement value is 00000000000000000000000000001001.
Var expr1 = 9;

// 5 is 00000000000000000000000000000101
Var expr2 = 5;

/*
00000000000000000000000000001001
&
00000000000000000000000000000101
=
00000000000000000000000000000001
=
1
*/

Var result = expr1 & expr2;

Alert (result );
// [1] is displayed]

Expr1 & = expr2;
Alert (expr1 );
// [1] is displayed]

JavaScript assignment operators and expressions


The JavaScript assignment operator is responsible for assigning values to variables. The JavaScript assignment operators include =, + =,-=, * =,/=, % =
The value assignment operator is connected to the operation object (operand). It is a regular JavaScript syntax expression. It is called a JavaScript value assignment expression.

JavaScript assignment operator and assignment expression syntax

Var I + =;

+ = -- Value assignment operator
The expression above indicates that I is assigned to the variable I by adding the value obtained by.

JavaScript value assignment operator and value assignment expression

Operator	=	+=	-=	*=	/=	%=
Name	Value assignment operator	Addition assignment operator	Subtraction assignment operator	Multiplication and assignment operators	Division assignment operator	Modulo value assignment operator (remainder value assignment operator)
Expression	I = 6	I + = 5	I-= 5	I * = 5	I/= 5	I % = 5
Example	Var I = 6;	I + = 5;	I-= 5;	I * = 5;	I/= 5;	I % = 5;
I result	6	11	1	30	1.2	1
Equivalent		I = I + 5;	I = I-5;	I = I * 5;	I = I/5;	I = I % 5;

Example

There are essential differences between the pre-auto-incrementing operators and the post-auto-incrementing operators. Their similarities are that they add 1 to themselves. The difference is that the pre-auto-incrementing operators Add 1 first, then use the value of the operand. Then, the auto-increment operator first uses the value of the operand and Adds 1. For example:

The Code is as follows:

Var;
Var I = 6;

// (Add before) after I add 1, I is equal to 7, and the I value is given to a, so a is equal to 7
A = ++ I;
Document. write (I );
Document. write ();

I = 6;
// (Add after) Assign the I value to a, so a is equal to 6. Finally, I add 1 and I is equal to 7.
A = I ++;
Document. write (I );
Document. write ();

Result:

The Code is as follows:

7
7
7
6