JavaScript Operators



= is used to assign values.

+ is used to add values.

The assignment operator = is used to assign values to JavaScript variables.

The arithmetic operator + is used to add values together.
Code:
y=5;
z=2;
x=y+z;
The value of x, after the execution of the statements above is 7.


JavaScript Arithmetic Operators

Arithmetic operators are used to perform arithmetic between variables and/or values.

Given that y=5, the table below explains the arithmetic operators:
Code:
Operator    Description                        Example            Result 
+             Addition                         x=y+2             x=7 y=5 
-             Subtraction                        x=y-2             x=3 y=5 
*             Multiplication                     x=y*2             x=10 y=5 
/             Division                         x=y/2             x=2.5 y=5 
%             Modulus (division remainder)     x=y%2             x=1 y=5 
++             Increment                         x=++y x=6 y=6     x=y++ x=5 y=6 
--             Decrement                         x=--y x=4 y=4     x=y-- x=5 y=4
JavaScript Assignment Operators

Assignment operators are used to assign values to JavaScript variables.

Given that x=10 and y=5, the table below explains the assignment operators:
Code:
Operator         Example         Same As         Result 
=                 x=y                             x=5 
+=                 x+=y             x=x+y             x=15 
-=                 x-=y             x=x-y             x=5 
*=                 x*=y             x=x*y             x=50 
/=                 x/=y             x=x/y             x=2 
%=                 x%=y             x=x%y             x=0
The + Operator Used on Strings

The + operator can also be used to add string variables or text values together.

To add two or more string variables together, use the + operator.
Code:
txt1="What a very";
txt2="nice day";
txt3=txt1+txt2;
After the execution of the statements above, the variable txt3 contains "What a verynice day".

To add a space between the two strings, insert a space into one of the strings:
Code:
txt1="What a very ";
txt2="nice day";
txt3=txt1+txt2;
or insert a space into the expression:
Code:
txt1="What a very";
txt2="nice day";
txt3=txt1+" "+txt2;
After the execution of the statements above, the variable txt3 contains:
Code:
"What a very nice day"
Adding Strings and Numbers

The rule is: If you add a number and a string, the result will be a string!
Example
Code:
x=5+5;
document.write(x);

x="5"+"5";
document.write(x);

x=5+"5";
document.write(x);

x="5"+5;
document.write(x);
Try it yourself