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Javascript Comparisons
Javascript Comparisons
Comparison Operators
Comparison operators are used in logical statements to determine equality or difference between variables or values, and test for true or false.
For example, given that x = 5, the table below explains the comparison operators:
Operator | Description | Comparing | Returns |
---|---|---|---|
== | equal to | x == 8 | false |
x == 5 | true | ||
x == "5" | true | ||
=== | equal value and equal type | x === 5 | true |
x === "5" | false | ||
!= | not equal | x != 8 | true |
!== | not equal value or not equal type | x !== 5 | false |
x !== "5" | true | ||
x !== 8 | true | ||
> | greater than | x > 8 | false |
< | less than | x < 8 | true |
>= | greater than or equal to | x >= 8 | false |
<= | less than or equal to | x <= 8 | true |
Oddities of Null, 0 and undefined
Equation | Returns |
---|---|
== | |
if (x ==1) | true if x = 1; |
if (x ==1) | true if x = "1"; |
if (x ==0) | true if x = 0; |
if (x ==0) | true if x = null; |
if (x ==0) | true if x = undefined; |
=== | |
if (x ===1) | true if x = 1; |
if (x ===1) | false if x = "'1"; |
if (x ===0) | true if x = 0; |
if (x ===0) | false if x = null; |
if (x ===0) | false if x = undefined; |