4.3. Operators
JavaScript has a number of operators that you might or might not be familiar with. These include the everpresent == (equals) and != (not equals), to which you have undoubtedly been exposed; there are a number of others. Although some of these operators are familiar, some others might not be as familiar, so Table 44 briefly touches upon these.
Table 44. JavaScript OperatorsOperator  Type  Description 

a + b  Arithmetic  Addition  a  b  Arithmetic  Subtraction  a* b  Arithmetic  Multiplication  a / b  Arithmetic  Division  a % b  Arithmetic  Modulus, the remainder to division  ++a  Arithmetic  Increment by one  a  Arithmetic  Decrement by one  a = b  Assignment  Set equal to  a += b  Assignment  Increment by the value on the right  a = b  Assignment  Decrement by the value on the right  a *= b  Assignment  Multiply by the value on the right  a /= b  Assignment  Divide by the value on the left  a %= b  Assignment  Modulus by the value on the right  a == b  Comparison  Equal to, value  a === b  Comparison  Equal to, value and type  a != b  Comparison  Not equal to  a > b  Comparison  Greater than  a < b  Comparison  Less than  a >= b  Comparison  Greater than/equal to  a <= b  Comparison  Less than/equal to  a && b  Logical  And  a  b  Logical  Or  !a  Logical  Not  a + b  String  String concatenation  a=(condition)?b:c  Comparison  Comparison operator  typeof(a)  Special  Returns a string consisting of the operand type  void a  Special  Suppresses the return of a variable 
I'll bet you didn't know that typeof was an operator.
