parseInt(): These functions were used to convert strings to numbers, but they are now considered deprecated in favor of the Number() and parseInt() functions, which provide more options and better support for different number formats.
Parameters: This function accepts two parameters as mentioned above and described below:
- Value: This parameter contains a string that is converted to an integer.
- radix: This parameter represents the radix or base to be used and it is optional.
Return value: It returns a number and if the first character can’t be converted to a number then the function returns NaN. It actually returns a number parsed up to that point where it encounters a character that is not a number in the specified radix(base).
Below is an example of the parseInt() function.
Using parseInt("3.14") = 3
Example 1: The n contains 2018 as ‘@’ is not a Number and parsing stops at that point, further characters are ignored.
Input: var n = parseInt("2018@geeksforgeeks"); Output: n = 2018
Input: var a = parseInt("1000"); Output: a = 1000(Number)
More example codes for the above function are as follows:
parseInt("100") = 100 parseInt("2018@geeksforgeeks") = 2018 parseInt("geeksforgeeks@2018") = NaN parseInt("3.14") = 3 parseInt("21 7 2018") = 21
Program 2: If the radix is not mentioned in the parseInt() function and the start of the string contains “0x” then it is treated as a hexadecimal value. By default, the radix is 10 (decimal). Note that in line 11 there is ‘8’ which is a character that is not defined in the radix 8 numeral system therefore it returns NaN.
parseInt("100",10) = 100 parseInt("8",8) = NaN parseInt("15",8) = 13 parseInt("16",16) = 22 parseInt(" 100 ") = 100 parseInt("0x16") = 22
- Google Chrome 1 and above
- Edge 12 and above
- Firefox 1 and above
- Internet Explorer 3 and above
- Safari 1 and above
- Opera 3 and above