Q3 - WebDez_CertPrep

How do you select an element with the ID "main-header" in CSS?

• .main-header {}

• #main-header {}

• main-header {}

• <main-header> {}

Answer explanation

To select an element with the ID 'main-header' in CSS, you use the '#' symbol followed by the ID name. Therefore, '#main-header {}' is the correct choice, while the other options are incorrect as they do not use the proper syntax for IDs.

What symbol is used to target an ID in CSS?

• . (dot)

• # (hashtag)

• @ (at symbol)

• * (asterisk)

Answer explanation

In CSS, the hashtag (#) is used to target an ID. For example, #myID selects the element with the ID 'myID'. The dot (.) is for classes, the at symbol (@) is for at-rules, and the asterisk (*) is a universal selector.

Which of the following is true about ID selectors in CSS?

• An ID can be used for multiple elements in an HTML document.

• An ID should be unique within an HTML document.

• An ID is the same as a class.

• IDs must start with a number.

Answer explanation

An ID should be unique within an HTML document, meaning it can only be assigned to one element. This ensures that styles and scripts targeting that ID affect only the intended element, unlike classes which can be reused.

Why would you use an ID selector instead of a class selector?

• When you want to style multiple elements the same way.

• When you need to apply a unique style to only one specific element.

• When you want to apply styles globally.

• There is no difference between IDs and classes.

Answer explanation

An ID selector is used to style a unique element, ensuring that the style applies to only one specific element on the page. In contrast, class selectors can be used for multiple elements.

What is wrong with following CSS rule?

#1header { color: blue; }

• The ID name should be written in quotes.

• IDs cannot start with a number.

• The # symbol is incorrect for an ID selector.

• The property color is not valid for an ID selector.

Answer explanation

The correct choice is that IDs cannot start with a number. In CSS, an ID selector must begin with a letter (a-z) or an underscore (_), making '#1header' invalid.

How do you assign an ID to an HTML element?

• <p class="header">Hello</p>

• <p id="header">Hello</p>

• <p #header>Hello</p>

• <p .header>Hello</p>

Which of these selects ALL page elements?

• # (hastag)

• . (dot)

• • * (asterisk)

• & (ampersand)

Answer explanation

The asterisk (*) is a wildcard selector in CSS that selects all elements on a page. The other options (#, ., &) have specific functions: # selects by ID, . selects by class, and & is not a valid selector.

Which of these requires <div> to be an immediate child of another <div>?

• div > div

• div, div

• div div

• div ~ div

Answer explanation

The selector 'div > div' specifies that the second

must be a direct child of the first

. This is the only option that enforces the immediate child relationship, making it the correct choice.

Which of these would select only images where class="logo"?

• .logo

• img.logo

• #logo

• img logo

• img > logo

Answer explanation

The correct choice, img.logo, selects only elements with the class 'logo'. The other options either select all elements with the class or are not valid selectors for images.

Which CSS selector selects all of the highlighted tags?

• a

• div.a

• a, ul

• #a

• a.href

Answer explanation

The selector 'a' selects all anchor tags in the document. The other options either target specific classes, IDs, or elements that do not match all highlighted tags, making 'a' the correct choice.