Popup

Popups are an additional way to show information, take user confirmation, or take user input from additional documents. A popup can navigate to a new URL and send information to the opener window. Alert box, Confirmation box, and Prompt box are the global functions where we can show the popup information.

1. alert(): It displays information to the user and has an "OK" button to proceed.

   alert("Alert message example");

2. confirm(): Use as a dialog box to confirm or accept something. It has "Ok" and "Cancel" to proceed. If the user clicks "Ok" then it returns true, if click "Cancel" it returns false.

   let txt;
   if (confirm("Press a button!")) {
     txt = "You pressed OK!";
   } else {
     txt = "You pressed Cancel!";
   }

3. prompt(): Takes user input value with "Ok" and "Cancel" buttons. It returns null if the user does not provide any input value.

   //syntax 
   //window.prompt("sometext","defaultText");
   
   let person = prompt("Please enter your name", "Harry Potter");
   
   if (person == null || person == "") {
     txt = "User cancelled the prompt.";
   } else {
     txt = "Hello " + person + "! How are you today?";
   }