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parseInt in JavaScript- How and when to use it?

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parseInt in JavaScript- How and when to use it?

Hey readers, in this article we will be discussing how to use the parseInt method in JavaScript in a step-wise, efficient manner. If you are a beginner and want to learn JavaScript then do check out the course on Codedamn.

Introduction to parseInt

JavaScript is one of the most used languages when it comes to building web applications as it allows developers to wrap HTML and CSS code in it to make web apps interactive. It allows a web application to be interactive. It is also used for making animations on websites and has a large community on GitHub. JavaScript has tons of libraries, one of which is React which we will be covering in this article later. 

Use cases: 

  • Building web server and its interactive functions
  • Animations and graphics, adding special effects to web components
  • Validating forms and exception errors
  • Adding behavior and functionalities to web pages

Since JavaScript is a scripting language, it works without any libraries. Developers are free to write JavaScript language code anywhere and can still run it in the browser. There is no structure in JavaScript, the browser executes each line of the code from top to down.

In Javascript, what is parseInt?

The parseInt function takes a string as its first parameter, parses it, and then returns an integer or NaN. If the first argument is not NaN, the return value is the integer converted to a number in the chosen radix.

The parseInt() function parses a string argument and returns an integer with the radix or base given.

ParseInt parses the value of the input, whereas Number() transforms the type. The parseInt will only parse up to the first non-digit character, as you can see. Number, on the other hand, will attempt to convert the full string.

The parseInt() function takes the string, radix as an argument, and converts it to an integer. The radix option specifies which numeral system to use; for example, a radix of 16 (hexadecimal) indicates that the number in the string should be converted from hexadecimal to decimal. It returns NaN, or not a number if the text does not include a numeric value.


parseInt(Value, radix)

Syntax of parseInt

The parseInt() method is represented by the following syntax:

Number.parseInt(string, radix) 

The string to be parsed is represented by the parameter string.

radix – This is an optional parameter. The number system to be utilized is represented by an integer between 2 and 36.

Return- The number is an integer. If the initial character cannot be translated to a number, it returns NaN.

The following parameters are accepted by this function, as mentioned above and described below:

This parameter’s value is a string that has been transformed into an integer.

radix: This argument is optional and represents the radix or base to be utilized.

The value returned: The function returns a number, and if the initial character cannot be translated to a number, it returns NaN. It actually returns a number that has been parsed until it comes across a character that isn’t a number in the chosen radix (base).

The parseInt() method in JavaScript is demonstrated in the following examples:

Example 1: The n contains 2018 since ‘@’ is not a Number and parsing terminates at that point, ignoring any additional characters.

Input: var n = parseInt(“2018@codedamn”);

Output: n = 2018

Example 2

Input: var a = parseInt(“1000”);

Output: a = 1000(Number)


This was about the parseInt method in JavaSript using HTML, if you want to learn more about javascript, do check out the article and course on Codedamn of javascript along with the course. Hope you liked this, if you have any queries or suggestions do let us know in the comments. 

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