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The Number.parseInt() method parses a string argument and returns an integer of the specified radix or base.


Number.parseInt(string,[ radix ])


The value to parse. If the string argument is not a string, then it is converted to a string (using the ToString abstract operation). Leading whitespace in the string argument is ignored.
An integer between 2 and 36 that represents the radix (the base in mathematical numeral systems) of the above mentioned string. Specify 10 for the decimal numeral system commonly used by humans. Always specify this parameter to eliminate reader confusion and to guarantee predictable behavior. Different implementations produce different results when a radix is not specified, usually defaulting the value to 10.

Return value

An integer number parsed from the given string. If the first character cannot be converted to a number, NaN is returned.


This method has the same functionality as the global parseInt() function:

Number.parseInt === parseInt; // true

and is part of ECMAScript 2015 (its purpose is modularization of globals). Please see parseInt() for more detail and examples.


if (Number.parseInt === undefined)
    Number.parseInt = window.parseInt;


Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Number.parseInt' in that specification.
Standard Initial definition.
ECMAScript Latest Draft (ECMA-262)
The definition of 'Number.parseInt' in that specification.
Living Standard  

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic Support(Yes)(Yes)25No(Yes)9
FeatureAndroidChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic Support(Yes)(Yes)(Yes)25No(Yes)9

See also

Document Tags and Contributors

 Last updated by: anonyco,