JavaScript Number.isFinite() Method

Below is the example of the Number.isFinite() Method. 

• Example:

Javascript

<script type="text/javascript">
    document.write(Number.isFinite(111));
</script>

• Output: 

true

The Number.isfinite() method in JavaScript is used to check whether the passed value is a finite number or not.

The Number.isfinite() method is different from the isfinite() method since this method doesn’t forcibly convert the parameter to a number and it does not return true for any value that is not of the type number. On the other hand, the global isfinite() method converts the tested value to a number first and then tests it.

Syntax:

Number.isFinite(value)

Parameters: This method accepts a single parameter value. It is the number which the user wants to check for finiteness.

Return Value: The number.isfinite() method returns a boolean value i.e. either true or false. It returns true if the passed value is of the type Number, and equates to a finite number else it returns false.

Below are some examples to illustrate the Number.isFinite() method in JavaScript:  

• Passing a negative number as an argument: If the negative number passed to the method is finite then the method will return true otherwise false. 

Javascript

<script type="text/javascript">
    document.write(Number.isFinite(-2));
</script>

Output: 

true

• Passing a positive number as an argument: If the positive number passed to the method is finite then the method will return true otherwise false. 

Javascript

<script type="text/javascript">
    document.write(Number.isFinite(2));
</script>

Output: 

true

• Passing zero as an argument: If zero is passed to the method then the method will return true as zero is a finite number. 

Javascript

<script type="text/javascript">
    document.write(Number.isFinite(0));
</script>

Output: 

true

• Passing an equation as an argument: If the equation evaluates to a finite number then the method will return true otherwise false. 

Javascript

<script type="text/javascript">
    document.write(Number.isFinite(7-3+2));
</script>

Output: 

true

• Passing an equation (resulting in infinite) as an argument: If the equation after evaluating does not gives a finite numeric value then the method will return false. 

Javascript

<script type="text/javascript">
    document.write(Number.isFinite(0/0));
</script>

Output: 

false

• Passing a word as an argument: Since a word is not of type integer, so the Number.isFinite() will not convert it to number and will return false.

Javascript

<script type="text/javascript">
    document.write(Number.isFinite("strong"));
</script>

Output: 

false

• Passing number(string) as an argument: Since a string is not of type integer, so the Number.isFinite() will not convert it to number and will return false. 

Javascript

<script type="text/javascript">
    document.write(Number.isFinite("5"));
</script>

Output: 

false

Supported Browsers:

• Google Chrome 19
• Internet Explorer 12
• Firefox 16
• Apple Safari 09
• Opera 15 and above