how to code text alerts in javascript code example

Example 1: javascript alert get text

var 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?";
}

Example 2: js alert format text

\b = Backspace 
\f = Form feed 
\n = New line 
\r = Carriage return 
\t = tab