Opening and closing tags in HTML - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an opening tag in HTML?

An opening tag is the start of an HTML element. It tells the browser to begin applying the element's effect or content. It looks like <tagname>.

beginner

What is a closing tag in HTML?

A closing tag marks the end of an HTML element. It looks like </tagname> and tells the browser to stop applying the element's effect.

beginner

Why do most HTML elements need both opening and closing tags?

Because the opening tag starts the element and the closing tag ends it. This helps the browser know where the element's content begins and ends, like a book chapter with a start and finish.

beginner

Give an example of an HTML element with opening and closing tags.

Example: <p>This is a paragraph.</p> Here, <p> is the opening tag and </p> is the closing tag. The text between them is the content.

beginner

Are there HTML tags that do not need closing tags? Give an example.

Yes, some tags are self-closing and do not need a closing tag. For example, <br> adds a line break and stands alone without a closing tag.

Which of these is a correct opening tag for a paragraph?

A &lt;p&gt;

B &lt;/p&gt;

C &lt;paragraph&gt;

D &lt;p/&gt;

The opening tag for a paragraph is <p>. The </p> is the closing tag.

What does a closing tag look like?

A &lt;/tagname&gt;

B &lt;tagname&gt;

C &lt;tagname/&gt;

D &lt;tagname&gt;&lt;/tagname&gt;

A closing tag has a slash before the tag name, like </tagname>.

Why do we need both opening and closing tags?

A To make the page colorful

B To start and end the element content

C To add images

D To create links only

Opening and closing tags tell the browser where the element content starts and ends.

Which tag is self-closing and does not need a closing tag?

A &lt;div&gt;

B &lt;h1&gt;

C &lt;br&gt;

D &lt;p&gt;

<br> is a self-closing tag that adds a line break without needing a closing tag.

What is wrong with this HTML? <p>Hello World<p>

A Opening tag is wrong

B No problem

C Text should be inside &lt;div&gt;

D Missing closing tag &lt;/p&gt;

The second <p> should be a closing tag </p> to properly end the paragraph.

Explain what opening and closing tags are in HTML and why they are important.

Think about how a book chapter has a start and an end.

Describe the difference between tags that need closing tags and self-closing tags with examples.

Some tags stand alone, others wrap content.

Practice

1. What is the purpose of an opening tag in HTML?

easy

A. To add comments inside the code

B. To close an element and stop the content

C. To start an element and tell the browser what content follows

D. To link to external files like CSS or JavaScript

Solution

1. Step 1: Understand what an opening tag does

   An opening tag tells the browser to start an element and what type it is, like <p> for a paragraph.

2. Step 2: Differentiate from other tags

   Closing tags end elements, comments add notes, and links connect files, so they are not the purpose of opening tags.

3. Final Answer:

   To start an element and tell the browser what content follows -> Option C

4. Quick Check:

   Opening tag = start element [OK]

Hint: Opening tags start elements; closing tags end them [OK]

Common Mistakes:

• Confusing opening tags with closing tags
• Thinking opening tags add comments
• Mixing opening tags with linking external files

2. Which of the following is the correct way to write a closing tag for a paragraph element?

easy

A. </p>

B. <p>

C. <p/>

D. <endp>

Solution

1. Step 1: Recall closing tag syntax

   Closing tags start with </ followed by the tag name, then >. For paragraph, it is </p>.

2. Step 2: Check each option

   <p> is an opening tag. Self-closing syntax like <p/> is not valid for paragraphs. <endp> is not a valid HTML tag.

3. Final Answer:

   </p> -> Option A

4. Quick Check:

   Closing tag = </tag> [OK]

Hint: Closing tags always start with [OK]

Common Mistakes:

• Using self-closing syntax for non-void elements
• Forgetting the slash in closing tags
• Writing invalid tag names

3. What will the browser display for this HTML snippet?

<h1>Welcome</h1><p>Hello World</p>

medium

A. Syntax error, nothing is displayed

B. WelcomeHello World (both on the same line)

C. Only Welcome is shown, Hello World is ignored

D. Welcome (big heading) and Hello World (paragraph below)

Solution

1. Step 1: Understand tag meanings

   <h1> creates a large heading, and <p> creates a paragraph below it.

2. Step 2: Predict browser rendering

   The browser shows "Welcome" as a big heading on one line, then "Hello World" as a paragraph on the next line.

3. Final Answer:

   Welcome (big heading) and Hello World (paragraph below) -> Option D

4. Quick Check:

   Heading + paragraph = separate lines [OK]

Hint: Headings and paragraphs display on separate lines [OK]

Common Mistakes:

• Thinking all text appears on one line
• Assuming paragraph is ignored
• Believing invalid syntax causes no display

4. Find the error in this HTML snippet:

<div>Hello<p>World</div></p>

medium

A. The <div> tag should be self-closing

B. The closing tags are in the wrong order

C. The <p> tag is not closed before

D. There is no error; this is valid HTML

Solution

1. Step 1: Check tag nesting rules

   HTML tags must close in the reverse order they open. Here, <div> opens first, then <p>. So </p> must close before </div>.

2. Step 2: Identify the error

   The snippet closes </div> before </p>, which breaks proper nesting.

3. Final Answer:

   The closing tags are in the wrong order -> Option B

4. Quick Check:

   Tags must close in reverse order [OK]

Hint: Close tags in reverse order of opening [OK]

Common Mistakes:

• Closing tags in the wrong order
• Using self-closing on container tags
• Ignoring nesting rules

5. You want to create a list with three items in HTML. Which snippet correctly uses opening and closing tags?

hard

A. <ul><li>Item 1</li><li>Item 2</li><li>Item 3</li></ul>

B. <ul><li>Item 1</li><li>Item 2</li><li>Item 3</ul></li>

C. <ul><li>Item 1</li><li>Item 2<li>Item 3</li></ul>

D. <ul><li>Item 1<li>Item 2<li>Item 3</ul>

Solution

1. Step 1: Understand list tag structure

   An unordered list <ul> contains list items <li>. Each <li> must have a matching closing tag </li>.

2. Step 2: Check each option for correct tag pairs

   The correct snippet <ul><li>Item 1</li><li>Item 2</li><li>Item 3</li></ul> closes every <li> with a matching </li>. Some options miss closing </li> tags, while another closes tags in the wrong order.

3. Final Answer:

   <ul><li>Item 1</li><li>Item 2</li><li>Item 3</li></ul> -> Option A

4. Quick Check:

   Every must have a closing [OK]

Hint: Close every <li> before starting the next [OK]

Common Mistakes:

• Skipping closing tags
• Closing tags in wrong order
• Mixing closing and tags