JavaScript comparison and logical operators
Comparison and logical operators for testing true or false.
Comparison
In comparison logic statements used to measure variables or values are equal.
| Operators | description | Compare | return value | Examples |
|---|---|---|---|---|
| == | equal | x == 8 | false | Examples >> |
| x == 5 | true | Examples >> | ||
| === | Absolutely equal to (value and type are equal) | x === "5" | false | Examples >> |
| x === 5 | true | Examples >> | ||
| ! = | not equal to | x! = 8 | true | Examples >> |
| ! == | Absolutely not equal to (or type a value not equal) | x! == "5" | true | Examples >> |
| x! == 5 | false | Examples >> | ||
| > | more than the | x> 8 | false | Examples >> |
| < | Less than | x <8 | true | Examples >> |
| > = | greater than or equal to | x> = 8 | false | Examples >> |
| <= | less than or equal to | x <= 8 | true | Examples >> |
how to use
You can use comparison operators in conditional statements to compare values, and then to take action based on the results:
if (age<18) x="Too young";
You will learn more about conditional statements in the next section of this tutorial.
Logical Operators
Logical operators used to determine the logic between variables or values.
Given x = 6 and y = 3, the table below explains the logical operators:
| 运算符 | 描述 | 例子 |
|---|---|---|
| && | and | (x < 10 && y > 1) 为 true |
| || | or | (x==5 || y==5) 为 false |
| ! | not | !(x==y) 为 true |
Conditional operator
JavaScript also contains certain conditions based on the variable conditions of the assignment operator.
grammar
variablename =( condition )? value1 : value2
example
Examples
If the variable age is less than 18, then assigned to the variable voteable "too young", otherwise assign "Age has been reached."
voteable=(age<18)?"年龄太小":"年龄已达到";
try it"