Reference Materials
Learn Python Interactively
Try for FreeJavaScript Built-In Functions
In JavaScript, built-in functions are the global functions that are called globally, rather than on an object.
In this reference page, you will find all the JavaScript built-in functions and their properties. For example, the parseInt() function returns an integer from a given string value.
JavaScript isFinite()
Checks if the passed value is a finite number
Javascript isNaN()
Checks if a value is NaN or not
JavaScript parseInt()
Parses string and returns integer of given radix
JavaScript parseFloat()
Parses argument and returns floating-point number