JavaScript parseFloat()Function

函数参考手册JavaScript Global Functions


Definition and Usage

The parseFloat() function parses a string and returns a floating-point number.

This function determines whether the first character in the string is a number. If so, it parses the string until it reaches the end of the number, then returns the number as a number, not as a string.

Syntax

parseFloat(string)

Parameter Description
string Required. The string to be parsed.


Browser Support

Internet ExplorerFirefoxOperaGoogle ChromeSafari

All major browsers support the parseFloat() function.


Tips and Notes

Note:Only the first number in the string is returned.

Note:Spaces at the beginning and end are allowed.

Note:If the first character of the string cannot be converted to a number, parseFloat() returns NaN.


Examples

Examples

Use parseFloat() to parse different strings:

document.write(parseFloat("10") + "<br>"); document.write(parseFloat("10.33") + "<br>"); document.write(parseFloat("34 45 66") + "<br>"); document.write(parseFloat(" 60 ") + "<br>"); document.write(parseFloat("40 years") + "<br>"); document.write(parseFloat("He was 40") + "<br>");

The output of the above example is:

10
10.33
34
60
40
NaN

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函数 参考手册JavaScript Global Functions

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