What is SetTimeout()?

Answer:

When you setTimeout it becomes asynchronous and it has to wait on the stack to get everything got finished.
setTimeout() method calls a function or evaluates an expression after a specified number of milliseconds.
Tip:1000 ms = 1 second.

Example:
setTimeout(function(){ alert("Hello"); }, 3000);
It will display an alert box after 3 seconds (3000 milliseconds)
Tip: The function is only executed once. If you need to repeat execution, use the setInterval() method.
Tip: Use the clearTimeout() method to prevent the function from running.