Introduction JavaScript Math.log() Function with Examples

In JavaScript, log() is a function that is used to return the natural logarithm of a number. Because the log() function is a static function of the Math object, it must be invoked through the placeholder object called Math.

Syntax

Math.log(x)

Parameter(s)

• x - It represents the number whose logarithm have to be get.

Return value

The log() function returns the natural logarithm of a number.

If the number is 0, the log() function will return -Infinity.

If the number is a negative value, the log() function will return NaN.

Browser Support:

• Google Chrome v1
• Internet Explorer v3
• Firefox v1
• Edge v12
• Opera
• Safari v1
• Android webview v1
• Chrome for Android v18
• Firefox for Android v4
• Opera for Android
• Safari on iOS v1
• Samsung Internet v1.0
• Node.js

Javascript Math.log() Method with Example

Example 1

Let’s take a look at an example of how to use the log() function in JavaScript.

console.log(Math.log(1));
console.log(Math.log(2.5));
console.log(Math.log(0));
console.log(Math.log(-4));

Output

0
0.9162907318741551
-Infinity
NaN

• In this example, the first output to the console log returned 0 which is the natural logarithm of 1.

• The second output to the console log returned 0.9162907318741551 which is the natural logarithm of 2.5.

• The third output to the console log returned -Infinity since the number provided was 0.

• The fourth output to the console log returned NaN since the number provided was a negative value.

Example 2

The Math.log() method cannot be used with complex arguments as only integer arguments are accepted.

console.log(Math.log(2+i));

Output

ReferenceError: i is not defined

Example 3

The following example demonstrates that if null is passed as an argument, then this method returns negative infinity.

var a = null;
var b = "";
var c = [];

console.log(Math.log(a));
console.log(Math.log(b));
console.log(Math.log(c));

Output

Infinity
Infinity
Infinity

Example 4

The following example demonstrates that if negative parameters are passed, this method returns NaN.

var a = -1;
var b = -2;
var c = Number.NEGATIVE_INFINITY;

console.log(Math.log(a));
console.log(Math.log(b));
console.log(Math.log(c));

Output

NaN
NaN
NaN

Example 5

The following code example demonstrates that if the passed value is not a valid number, then the method returns NaN.

var a = "JavaScript";
var b;

console.log(Math.log(a));
console.log(Math.log(b));

Output

NaN
NaN

Thanks for reading !

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