| Arithmetic | a = 12, b = 4 | ||||
| + - * / % ++ – – |
Addition Subtraction Multiplication Division Modulus Increment Decrement |
a a a a a a a |
+ - * / % ++ – – |
b b b b b |
16 8 48 3 0 13 11 |
| Assignment | a = 12, b = 4 | ||||
| = += -= *= /= %= |
Assign to Add and assign Subtract and assign Multiply and assign Divide and assign Modulus and assign |
a a a a a a |
= += -= *= /= %= |
b b b b b b |
b now equals 12 a now equals 4 a now equals 8 a now equals 48 a now equals 3 a now equals 0 |
| Comparison | a = 12, b = 4 | ||||
| == != > < >= <= |
Equality Inequality Greater than Less than Greater than or equal Less than or equal |
a a a a a a |
== != > < >= <= |
b b b b b b |
false true true false true false |
| Logical | a = 12, b = 4 | ||||
| && || ! |
And OR NOT |
a a a |
&& || ! |
b b b |
true true !(a||b) = false reverses condition |
| Conditional | a = 12, b = 4 | ||||
| a > ? : | Ternary | a > b | ? car | : bike | car |
typeof
Unary operator placed before a single operand (which can be of any type) and returns true or false based on an evaluation or a string indicating the data type of the operand.
| Number | "number" |
| String | "string" |
| Boolean | "boolean" |
| Object | "object" |
| Function | "function" |
| Undefined | "undefined" |
| Null | "object" |
<html>
<head>
<title>JavaScript</title>
</head>
<body>
<script type="text/javascript">
var a = 42;
var b = "This is my car";
result = (typeof a == "string" ? "a is a string" : "a is a number");
document.write(result + "<br>"); //note use of + for concatenation
document.write("b is a ");
document.write(typeof b);
</script>
</body>
</html>
Save & refresh browser:
| a is a number b is a string |