#### JS Operators

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

The arithmetic operator + is used to add values together.

 a=5;b=7;c=a+b;

The value of c, after the execution of the statements above is 12.

#### JS 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:

 Operator Description Example Result + Addition x=y+2 x=7 – Subtraction x=y-2 x=3 * Multiplication x=y*2 x=10 / Division x=y/2 x=2.5 % Modulus (division remainder) x=y%2 x=1 ++ Increment x=++y x=6 — Decrement x=–y x=4

#### JS 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:

 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.

 txt1=”What a very”;txt2=”nice day”;txt3=txt1+txt2;

After the execution of the statements above, the variable txt3 contains “What a very nice day”.

To add a space between the two strings, insert a space into one of the strings:

 txt1=”What a very “;txt2=”nice day”;txt3=txt1+txt2;

or insert a space into the expression:

 txt1=”What a very”;txt2=”nice day”;txt3=txt1+” “+txt2;

After the execution of the statements above, the variable txt3 contains:

“What a very nice day”

Look at this example:

`<html><body><script type="text/javascript">x=5+5;document.write(x);document.write("<br />");x="5"+"5";document.write(x);document.write("<br />");x=5+"5";document.write(x);document.write("<br />");x="5"+5;document.write(x);document.write("<br>");</script><p>The common rule is: If you add a number and a string,the result will be a string.</p></body></html>`

The rule is: If we add a number and a string, the result will be a string.

#### JS Comparison Operators

JS comparison operators are used in logical statements to determine equality or difference between variables or values.

Given that x=5, the table below explains the comparison operators:

 Operator Description Example == is equal to x==8 is false === is exactly equal to (value and type) x===5 is truex===”5″ is false != is not equal x!=8 is true > is greater than x>8 is false < is less than x<8 is true >= is greater than or equal to x>=8 is false <= is less than or equal to x<=8 is true
##### How can it be used

Comparison operators can be used in conditional statements to compare values and take action depending on the result:

 if (age<18) document.write(“Too young”);

#### JS Logical Operators

JS Logical operators are used to determine the logic between variables or values.

Given that x=6 and y=3, the table below explains the logical operators:

 Operator Description Example && and (x < 10 && y > 1) is true || or (x==5 || y==5) is false ! not !(x==y) is true

#### JS Conditional Operator

JavaScript also contains a conditional operator that assigns a value to a variable based on some condition.

##### Syntax
 variable_name = (condition)?value1:value2
##### Example
 greeting = (visitor==”PRES”) ? “Dear PM” : “Dear “;

If the variable visitor has the value of “PRES”, then the variable greeting will be assigned the value “Dear PM” else it will be assigned “Dear”.