JavaScript Q&A: alert, prompt, and confirm #5

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JavaScript Interaction Q&A: alert, prompt, and confirm

Below is a collection of questions and answers designed to deepen your understanding of JavaScript’s interaction functions, along with code snippets for clarity.

1. What is a modal window, and why is it called that?

Ans:
A modal window is a popup that forces the user to interact with it before continuing to use the rest of the page. For example:

alert("This modal window blocks further interaction until dismissed.");

It’s “modal” because it creates a mode where the underlying page is inactive.

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2. How does the alert function work in JavaScript?

Ans:
The alert function displays a message in a modal dialog and halts script execution until the user clicks “OK.”

alert("This is an alert message!");
// Code here will execute only after the alert is closed.

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3. What are the two arguments accepted by the prompt function?

Ans:
The prompt function accepts:

• A message (string) to display.

• An optional default value for the input field.

let response = prompt("What is your favorite color?", "Blue");
console.log("User's favorite color is:", response);

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4. What happens when a user presses "Cancel" in a prompt dialog?

Ans:
If the user clicks "Cancel," the prompt returns null:

let input = prompt("Enter a value:", "Default");
if (input === null) {
  console.log("User canceled the prompt.");
}

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5. Why is it recommended to always provide a default value in prompt when using Internet Explorer?

Ans:
Without a default value, Internet Explorer might display "undefined" as the default text. Providing a default value (even an empty string) avoids this issue:

let testInput = prompt("Type something:", ""); // Prevents 'undefined' from appearing

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6. What does the confirm function return when the user presses "OK" and when they press "Cancel"?

Ans:
The confirm function returns:

• true if the user clicks “OK.”

• false if the user clicks “Cancel.”

let userDecision = confirm("Do you agree?");
console.log("User's decision:", userDecision); // true for OK, false for Cancel

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7. What are the two main limitations of alert, prompt, and confirm dialogs?

Ans:
They have two key limitations:

• Fixed Location: The browser controls where these dialogs appear.

    alert("I always appear centered by default!");
  

• No Custom Styling: Their appearance cannot be altered with CSS.

    // No CSS can change the style of these dialogs.
    alert("I have a default design that cannot be styled.");
  

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8. How does a confirm dialog differ from an alert dialog?

Ans:

• An alert shows a message and has only an "OK" button.

• A confirm provides "OK" and "Cancel" buttons, returning a boolean value.

// Alert example:
alert("This is just an alert.");

// Confirm example:
let decision = confirm("Do you want to proceed?");
console.log("Decision:", decision);

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9. What will be the output of the following code if the user enters "John" in the prompt?

Ans:

let answer = prompt("Enter your name:", "Guest");
alert(`Welcome, ${answer}!`);

If the user types "John" and clicks OK, the output will be:

// Output in the alert dialog:
"Welcome, John!"

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Thank you!