JavaScript parseFloat()

parseFloat() is a JavaScript method that converts a string containing numeric data into its number counterpart. parseFloat() in JavaScript takes the input string as its argument and produces the parsed output, in number format, as its return value.

Syntax of parseFloat() in Javascript

The following is the syntax of parseFloat() in Javascript:

The syntax of parseFloat() in JavaScript is pretty straightforward. Since it is a JavaScript method, we just have to give the string, which we wish to parse, as its argument, and then the parseFloat() method will give us the parsed result as its returned value.

Parameters of parseFloat() Function in Javascript

The following is the parameter of parseFloat() in Javascript:

• string: The parseFloat() takes only one parameter that is the string that we wish to parse.

If we give a second parameter to parseFloat(), that parameter is ignored.

Return Value of parseFloat() in Javascript

Return Type: number

As discussed above, the return value of parseFloat() is the parsed value, in number format. And, in cases, when parseFloat() is unable to parse, it simply returns NaN.

The below image depicts the input (the argument) taken by parseFloat() , and the output (the return value) produced by parseFloat().

Exceptions of parseFloat() Function in Javascript

The parseFloat() function in JavaScript does not throw exceptions; instead, it returns NaN when unable to parse a number from the string. This ensures graceful handling of non-numeric inputs without interrupting code execution.

Example of parseFloat() in JavaScript

The following is an example of parseFloat() in javascript.

The output will be 127.

More Examples of parseFloat() in Javascript

Example 1: parseFloat returning a number

1. When there are non-numeric characters in the latter part of the input string.

Explanation:

In such cases, parseFloat() extracts the numeric part string only.

2. When there are multiple decimal points.

Explanation:

In such cases, parseFloat() extracts the initial portion of the input string, which makes a floating-point number because a floating-point number cannot have two decimal points.

3. When the input string has the exponential character

Explanation:

From the above code snippet, it can be seen that, in all the cases, parseFloat() is successful in parsing into a number when the input string has the exponential character.

4. When there are leading or trailing whitespaces

Explanation:

As we can see in the above code snippet, both leading and trailing whitespaces are ignored by parseFloat(). Moreover, it is worthwhile to note here that parseFloat() does not force to produce a floating-point number when the input string contains integer numeric data. In such a case, parseFloat() just converts the integer string to an integer number.

5. When there is a leading minus or plus sign

Explanation:

When there is a minus sign before a numeric character, parseFloat() interprets it to be a negative number. On the other hand, when there is a plus sign before a numeric character, parseFloat() interprets it to be a positive number.

Example 2: parseFloat returning NaN

Explanation:

As we can see in the above example, parseFloat() in JavaScript returns NaN when it cannot convert the first non-whitespace character of the input string into a number..

Browser Compatibility

The parseFloat() function in JavaScript is universally supported across all major web browsers, ensuring consistent parsing of strings into floating-point numbers. This widespread compatibility means developers can reliably use the parseFloat() function in JavaScript without worrying about browser-specific issues, making it a dependable choice for numerical data processing in web applications.

See Also

• parseFloat() as in mdn web docs
• parseInt() as in javaTpoint