Built-in JavaScript objects and functions are ones you'll use all the time. Here's how to use Object, JSON, String, Math, Date, and console in your JavaScript programs.

If you want to create a Date object for the current date and time of the system, use the Date constructor without passing any argument. You can also use the Date.now() function for the same task.

preload this image for faster response time, we simply create a new Image() object, called heavyImage , and load it simultaneously to the page with the onLoad() event handler: ...