JavaScript Operators Summary _javascript tips

In JavaScript, the common operators are the arithmetic, comparison, and logic operators.

Table 1 JavaScript Common operators

Arithmetic Operators	Description	examples	Results
=	The assignment operator. Assigns the value of the right-hand variable of the operator to the left variable.	x = 5;	-
+	Plus. Adds two data.	y=1+2;	Y=3
-	Minus sign. Subtracts two data.	z = x-y;	z=2
*	Multiplication Multiplies two data.	A=x*y;	A=15
/	Division Divides two data.	b=x/z;	b=2.5
%	The remainder operation. Find the remainder of the two data division.	C=x%z;	C=1
++	Self added. Add an operand of 1.	M=++x;	M=6 x=6
--	Self reduction. Reduce the number of operands by 1.	N=--x;	N=5 x=5
comparison Operators	Description	examples	Results
==	Equal. Returns true if the two data are equal, or false.	Boolean1= (x==5);	Boolean1=true
!=	Not equal. Returns true if the two data are not equal, or false.	Boolean2= (x!=5);	Boolean2=false;
>	Greater than. Returns true if the left data is greater than the right data, otherwise returns false.	Boolean4= (X>y);	Boolean4=true
<	Less than. Returns a Boolean value of True if the left data is less than the right data, otherwise returns false.	Boolean5= (X<y);	Boolean5=false
>=	is greater than or equal to. Returns true if the left data is greater than or equal to the right data, otherwise returns false.	Boolean6= (x>=y);	Boolean6=true
<=	is less than or equal to. Returns true if the left data is less than or equal to the right data, otherwise returns false.	Boolean7= (x<=y);	Boolean7=false
logical Operators	Description	examples	Results
&&	Logic and. Returns true if the operands on both sides of the symbol are true, or false.	boolean_a=true&&false;	Boolean_a=false
||	Logical OR. Returns False if the operands on both sides of the symbol are false, otherwise true.	boolean_b=true| | False	Boolean_b=true
!	Logic is not. Returns False if the operand to the right of the symbol is true, otherwise returns true.	Boolean_c=!true;	Boolean_c=false

The "+" number can also be used to connect strings

The "+" number can be used not only to add two data, but also to connect strings.

For example:

Copy Code code as follows:

var name= "Tom";
var age=22;
var person= ' My name is ' +name+ '! I ' m ' +age+ '! ";
alert (person);

Save and run the code to display my name is Tom! I ' m 22!

In the example above, there are strings and numbers. When a string is mixed with a numeric value, JavaScript automatically determines whether the "+" number works, whether it is a summation operation or a connection string. If this is a connection string, the numeric value is also converted to a string.

Discussion on self-addition (+ +) and self-reduction (-)

It is noteworthy that the self-addition (+ +) and decrement (-) operators are placed before and after the operands in a different meaning. Put in front of operand (before plus/before self reduction), the operand is added 1 (minus 1), then the operation is placed after the operand (after the addition/after the self-subtraction), the first operation, and then the operand plus 1 (minus 1).

For example:

Copy Code code as follows:

<script type= "Text/javascript" >
var x=5;
var y=++x; The value of x after the assignment is 6
var z=x++; The value of x after the assignment is 7
var m=--x//Ex-minus, value x after assignment is 6
var n=x--//After self reduction, value of X after assignment is 5
</script>
<p onclick= "alert (y);" > Show Y's value </p>
<p onclick= "alert (z);" > Show Z's value </p>
<p onclick= "alert (m);" > Show M's Value </p>
<p onclick= "alert (n);" > shows the value of n </p>

Save and run the code, click Four paragraphs in turn, and show 6.

Analysis:

For y, X (x=5) plus 1, the value becomes 6, and then the value of x is passed to Y.
For z, the value of x (x=6) is passed to Z first, then x plus 1, and the value becomes 7.
For M, X (x=7) minus 1, the value is 6, and then the value of x is passed to M.
For N, first pass the value of X (x=6) to N, minus 1 to X, and the value to 5.

Abbreviation for arithmetic operator

JavaScript also supports abbreviations for common mathematical operators for easy operation and less code writing.

Table 2 abbreviations for common arithmetic operators

operator	Example	equivalent to
+=	X+=y	X=x+y
-=	X-=y	X=x-y
*=	X*=y	X=x*y
/=	X/=y	x=x/y
%=	X%=y	X=x%y

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