How to Convert User Input from a Prompt Box to a Numeric Value in JavaScript?

Retrieving Numeric Input from Prompt Box

Converting user input from a prompt box to a numeric value is crucial for performing mathematical calculations in JavaScript. This conversion can be achieved through the functions parseInt() and parseFloat().

parseInt() and parseFloat()

parseInt() and parseFloat() parse a string representation of a number into a numeric value.

Syntax:

• parseInt(string, radix): Parses the string as an integer, optionally specifying the radix for the numeral system (default is 10).
• parseFloat(string): Parses the string as a floating-point number.

Example:

<code class="javascript">var x = prompt("Enter a Value", "0");
var y = prompt("Enter a Value", "0");
var num1 = parseInt(x);
var num2 = parseInt(y);</code>

This code converts the user input from strings to integers and stores them in the variables num1 and num2. These values can now be used for calculations.

Additional Tips:

• Specifying the radix: For numeric systems other than 10 (e.g., hexadecimal), specify the radix in the parseInt() function (e.g., `parseInt("100", 16) for hexadecimal 100).
• Error Handling: parseInt() and parseFloat() may return NaN (Not-a-Number) if the input string cannot be parsed. Handle this case to ensure error-free calculations.

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