What is the use of alert box with its syntax and parameters?

Answer 1

alert box is the one which pops out of browser window and alerts the user with some message

for eg: Sometimes when submitting forms..if user has not filled all the required contents then a alert box saying " please fill all the required (*) contents before submitting form." will pop out.

alert(); is a JavaScript function that takes a string as an input (optional) and creates an alert box with the message as the string that is received as parameter

Syntax for alert box in JavaScript :

alert("message that u want to display ");