Cell merging in HTML - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does colspan attribute do in an HTML table?

The colspan attribute makes a table cell span across multiple columns, merging those cells horizontally into one.

beginner

What is the purpose of the rowspan attribute in HTML tables?

The rowspan attribute makes a table cell span across multiple rows, merging those cells vertically into one.

beginner

How do you merge a cell across 3 columns in an HTML table?

Add colspan="3" inside the <td> or <th> tag to merge that cell across 3 columns.

intermediate

Can you merge cells both horizontally and vertically in the same table?

Yes, you can use colspan to merge cells horizontally and rowspan to merge cells vertically in the same table.

intermediate

What happens if you use colspan or rowspan incorrectly in a table?

The table layout may break or look uneven because the browser tries to fit merged cells but the total columns or rows don't match properly.

Which attribute merges cells horizontally in an HTML table?

A merge

B rowspan

C span

D colspan

colspan merges cells horizontally by spanning columns.

How do you merge a cell vertically across 2 rows?

A <code>merge="2"</code>

B <code>colspan="2"</code>

C <code>rowspan="2"</code>

D <code>span="2"</code>

rowspan="2" merges the cell vertically across 2 rows.

What tag do you add colspan or rowspan to?

A <code>&lt;table&gt;</code>

B <code>&lt;td&gt;</code> or <code>&lt;th&gt;</code>

C <code>&lt;tbody&gt;</code>

D <code>&lt;tr&gt;</code>

You add colspan or rowspan to table cells: <td> or <th>.

If a cell has colspan="3", how many columns does it cover?

A 3

B 2

C 1

D 4

The cell covers 3 columns horizontally.

What might happen if you use rowspan incorrectly?

A Table layout may break or look uneven

B Table cells will automatically fix themselves

C Nothing, it is ignored

D Browser crashes

Incorrect use of rowspan can break the table layout or make it look uneven.

Explain how to merge cells horizontally and vertically in an HTML table.

Think about how columns and rows can be combined using attributes.

Describe common mistakes when using cell merging in tables and how they affect the table display.

Consider what happens if merged cells don't fit the table structure.

Practice

1. What does the colspan attribute do in an HTML table?

easy

A. It merges cells horizontally across columns.

B. It merges cells vertically across rows.

C. It changes the color of a cell.

D. It adds a border around a cell.

Solution

1. Step 1: Understand the purpose of colspan

   The colspan attribute is used in a table cell to make it span across multiple columns horizontally.

2. Step 2: Compare with rowspan

   rowspan merges cells vertically across rows, so it is different from colspan.

3. Final Answer:

   It merges cells horizontally across columns. -> Option A

4. Quick Check:

   colspan = horizontal merge [OK]

Hint: Remember: colSpan = column span (horizontal) [OK]

Common Mistakes:

• Confusing colspan with rowspan
• Thinking colspan changes cell style
• Assuming colspan merges rows

2. Which of the following is the correct syntax to merge two columns in a table cell?

easy

A. <td rowspan='2'>Merged</td>

B. <td merge='2'>Merged</td>

C. <td colspan='2'>Merged</td>

D. <td span='2'>Merged</td>

Solution

1. Step 1: Identify the correct attribute for column merging

   The attribute to merge columns is colspan, so it should be used as colspan='2'.

2. Step 2: Check syntax correctness

   <td colspan='2'>Merged</td> uses the correct attribute and syntax: <td colspan='2'>Merged</td>. Other options use wrong attributes or invalid syntax.

3. Final Answer:

   <td colspan='2'>Merged</td> -> Option C

4. Quick Check:

   Correct attribute for columns = colspan [OK]

Hint: Use colspan='number' to merge columns [OK]

Common Mistakes:

• Using rowspan instead of colspan
• Using non-existent attributes like merge or span
• Missing quotes around attribute value

3. What will be the visual result of this HTML snippet?

<table border='1'>
  <tr>
    <td rowspan='2'>A</td>
    <td>B</td>
  </tr>
  <tr>
    <td>C</td>
  </tr>
</table>

medium

A. All cells appear in a single row.

B. Cell 'A' spans two rows vertically, cells 'B' and 'C' are side by side horizontally.

C. Cell 'A' spans two columns horizontally, cells 'B' and 'C' are below 'A'.

D. Cell 'A' spans two rows vertically, cells 'B' and 'C' are stacked vertically next to 'A'.

Solution

1. Step 1: Understand rowspan effect

   The rowspan='2' on cell 'A' makes it cover two rows vertically in the first column.

2. Step 2: Analyze placement of cells 'B' and 'C'

   Cell 'B' is in the first row, second column; cell 'C' is in the second row, second column. They stack vertically next to the tall 'A' cell.

3. Final Answer:

   Cell 'A' spans two rows vertically, cells 'B' and 'C' are stacked vertically next to 'A'. -> Option D

4. Quick Check:

   rowspan = vertical merge [OK]

Hint: Rowspan stacks cells vertically beside merged cell [OK]

Common Mistakes:

• Thinking rowspan merges columns horizontally
• Assuming cells B and C are side by side horizontally
• Confusing rowspan with colspan

4. Identify the error in this table code that tries to merge cells across two columns:

<table border='1'>
  <tr>
    <td colspan='2'>Merged</td>
    <td>Cell 3</td>
  </tr>
  <tr>
    <td>Cell 4</td>
    <td>Cell 5</td>
  </tr>
</table>

medium

A. Second row has only two cells but first row has three columns, causing layout mismatch.

B. The colspan attribute value should be '3' instead of '2'.

C. The colspan attribute is not allowed on td elements.

D. The table is missing a thead section.

Solution

1. Step 1: Count columns in first row

   The first row has a cell with colspan='2' plus one more cell, so total columns = 2 + 1 = 3.

2. Step 2: Count columns in second row

   The second row has only two cells, so only 2 columns, which causes a mismatch in table layout.

3. Final Answer:

   Second row has only two cells but first row has three columns, causing layout mismatch. -> Option A

4. Quick Check:

   Column count must match in all rows [OK]

Hint: Ensure all rows have same total columns after colspan [OK]

Common Mistakes:

• Ignoring column count mismatch
• Thinking colspan value must match total columns
• Believing colspan is invalid on <td>

5. You want to create a table where the top-left cell spans 2 rows and 3 columns. Which is the correct way to write this cell?

hard

A. <td rowspan='3' colspan='2'>Top Left</td>

B. <td rowspan='2' colspan='3'>Top Left</td>

C. <td colspan='2' rowspan='3'>Top Left</td>

D. <td colspan='3'>Top Left</td>

Solution

1. Step 1: Identify correct rowspan and colspan values

   The cell should span 2 rows vertically and 3 columns horizontally, so rowspan='2' and colspan='3' are needed.

2. Step 2: Check attribute order and correctness

   Attributes can be in any order, but <td rowspan='2' colspan='3'>Top Left</td> correctly uses rowspan='2' and colspan='3'. Other options have swapped or incorrect values.

3. Final Answer:

   <td rowspan='2' colspan='3'>Top Left</td> -> Option B

4. Quick Check:

   Rowspan = rows, colspan = columns [OK]

Hint: Use rowspan for rows, colspan for columns together [OK]

Common Mistakes:

• Swapping rowspan and colspan values
• Using wrong numbers for spans
• Omitting one of the attributes