1var proceed = confirm("Are you sure you want to proceed?");
2if (proceed) {
3  //proceed
4} else {
5  //don't proceed
6}

1Copyvar name = window.prompt("Enter your name: ");
2alert("Your name is " + name);

1var answer = prompt("How are you? ");

1var answer = prompt('What is your name?','Joe Blogg');

1var person = prompt("Please enter your name", "Harry Potter");
2
3if (person != null) {
4  document.getElementById("demo").innerHTML =
5  "Hello " + person + "! How are you today?";
6}