alert()
alert("Hello! I am an alert box!!");
prompt()
var person = prompt("Please enter your name", "Harry Potter"); if (person != null) { document.getElementById("demo").innerHTML = "Hello " + person + "! How are you today?"; }
confirm()
var txt; var r = confirm("Press a button!"); if (r == true) { txt = "You pressed OK!"; } else { txt = "You pressed Cancel!"; }