JavaScript #4: DOM

What does the following code do?

• Changes the content of the element with ID "header" to "Welcome"

• Changes the background color of the element with ID "header"

• Adds a new element with ID "Welcome"

• Removes the element with ID "header"

Answer explanation

Changes the content of the element with ID "header" to "Welcome"

What will be the result of the following code?

• Adds a new paragraph element with text to the document.

• Removes all paragraph elements from the document.

• Replaces the first paragraph in the document.

• Does nothing because the code is incorrect.

Answer explanation

Adds a new paragraph element with text to the document

What does the following event listener do?

• Displays an alert when any button is clicked.

• Displays an alert when the button with ID "myButton" is clicked.

• Adds a new button to the document.

• Changes the text of the button with ID "myButton".

Answer explanation

Displays an alert when the button with ID "myButton" is clicked

What does the following code accomplish?

• It adds an image with source "image.jpg" to the document.

• It replaces all images in the document with "image.jpg".

• It removes all images from the document.

• It does nothing because setAttribute is incorrect.

What is the purpose of the following code?

• Changes the color of all elements with class "item" to red.

• Changes the background color of all elements with class "item" to red.

• Changes the text content of all elements with class "item" to "red".

• Changes the color of only the first element with class "item" to red.

What does the following code accomplish?

• Adds a new list item "New item" to the first <ul> in the document

• Replaces the first list item in the <ul> with "New item"

• Removes all items from the <ul> and adds "New item"

• Does nothing because the code is incorrect

What will happen when the following code is executed?

• Nothing, as no error will be thrown

• Displays "Error occurred!" in an alert box

• Stops the execution of the script

• Throws a syntax error

Answer explanation

Nothing, as no error will be thrown (Dividing by zero does not throw an error in JavaScript)

What will the following code return?

• 1 (one day difference)

• 0 (no difference)

• 24 (24 hours difference)

• -1 (negative difference)

What is the value of result after executing the following code?

• Any integer between 1 and 10, inclusive

• Any integer between 0 and 10, inclusive

• Any integer between 1 and 9, inclusive

• Any integer between 0 and 9, inclusive

What does the following code return?

• 2

• 3

• 8

• 15