Comparison and Logical operators are used to test for true or false
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:
| Operators | Description | Comparing | Returns |
| == | equal to | x==8 | false |
| x==5 | true | ||
| === | exactly equal to | x==="5" | false |
| (equal to value and equal type) | x===5 | true | |
| != | not equal | x!8 | true |
| !== | not equal (different values | x!=="5" | true |
| or different type) | x!==5 | false | |
| > | 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 |
Logical Operators are used to mark the relationship. Different variables or values
Given that x=6 and y=3, the table below explains the logical operators:
Operators Description Example
&& and (x < 10 && y > 1) is true
|| or (x==5 || y==5) is false
! not !(x==y) is true
Conditional Operators
JavaScript also contains a conditional operato that assigns a value to a variable based on some condition.
Syntax
variablename=(condition)?value1:value2
Example: If the variable age is a value below 18, the value f the variable voteable will be "Too young, otherwise the value of voteable will be "Old enough":
<html>
<body>
<p>Click the button to check the age.</p>
Age:<input id="age" value="18" />
<p>Old enough to vote?</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction()
{
var age,voteable;
age=document.getElementById("age").value;
voteable=(age<18)?"Too young":"Old enough";
document.getElementById("demo").innerHTML=voteable;
}
</script>
</body>
</html>
This is the result:
Next
{--mlinkarticle=2955--}Chapter 12 - JavaScript Conditions{--mlinkarticle--}