[html] How do you use colspan and rowspan in HTML tables?

I don't know how to merge rows and columns inside HTML tables.

Can you please help me with making such a table in HTML?

If you're confused how table layouts work, they basically start at x=0, y=0 and work their way across. Let's explain with graphics, because they're so much fun!

When you start a table, you make a grid. Your first row and cell will be in the top left corner. Think of it like an array pointer, moving to the right with each incremented value of x, and moving down with each incremented value of y.

For your first row, you're only defining two cells. One spans 2 rows down and one spans 4 columns across. So when you reach the end of your first row, it looks something like this:

<table>
    <tr>
        <td rowspan="2"></td>
        <td colspan="4"></td>
    </tr>
</table>

Now that the row has ended, the "array pointer" jumps down to the next row. Since x position 0 is already taken up by a previous cell, x jumps to position 1 to start filling in cells. * See note about difference between rowspans.

This row has four cells in it which are all 1x1 blocks, filling in the same width of the row above it.

<table>
    <tr>
        <td rowspan="2"></td>
        <td colspan="4"></td>
    </tr>
    <tr>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
</table>

The next row is all 1x1 cells. But, for example, what if you added an extra cell? Well, it would just pop off the edge to the right.

<table>
    <tr>
        <td rowspan="2"></td>
        <td colspan="4"></td>
    </tr>
    <tr>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
</table>

* But what if we instead (rather than adding the extra cell) made all these cells have a rowspan of 2? The thing you need to consider here is that even though you're not going to be adding any more cells in the next row, the row still must exist (even though it's an empty row). If you did try to add new cells in the row immediately after, you'd notice that it would start adding them to the end of the bottom row.

<table>
    <tr>
        <td rowspan="2"></td>
        <td colspan="4"></td>
    </tr>
    <tr>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td rowspan="2"></td>
        <td rowspan="2"></td>
        <td rowspan="2"></td>
        <td rowspan="2"></td>
        <td rowspan="2"></td>
    </tr>
    <tr>
        <td></td>
    </tr>
</table>

Enjoy the wonderful world of creating tables!

The property you are looking for that first td is rowspan: http://www.angelfire.com/fl5/html-tutorial/tables/tr_code.htm

<table>
<tr><td rowspan="2"></td><td colspan='4'></td></tr>
<tr><td></td><td></td><td></td><td></td></tr>
<tr><td></td><td></td><td></td><td></td><td></td></tr>
</table>

It is similar to your table

  <table border=1 width=50%>
<tr>
    <td rowspan="2">x</td> 
    <td colspan="4">y</td>
</tr>
<tr>
    <td bgcolor=#FFFF00 >I</td>
    <td>II</td>
    <td bgcolor=#FFFF00>III</td>
    <td>IV</td>
</tr>
<tr>
    <td>empty</td>
    <td bgcolor=#FFFF00>1</td>
    <td>2</td>
    <td bgcolor=#FFFF00>3</td>
    <td>4</td>
</tr>

If anyone is looking for a rowspan on both the left AND on the right, here is how you can do it:

table { _x000D_
    border-collapse: collapse;_x000D_
}_x000D_
_x000D_
td {_x000D_
    padding: 20px; _x000D_
    border: 1px solid black; _x000D_
    text-align: center;_x000D_
}

<table>_x000D_
    <tbody>_x000D_
    <tr>_x000D_
        <td rowspan="2">LEFT</td>_x000D_
        <td> 1 </td>_x000D_
        <td> 2 </td>_x000D_
        <td> 3 </td>_x000D_
        <td> 4 </td>_x000D_
        <td rowspan="2">RIGHT</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
        <td> 5 </td>_x000D_
        <td> 6 </td>_x000D_
        <td> 7 </td>_x000D_
        <td> 8 </td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
    </tr>_x000D_
    </tbody>_x000D_
</table>

Alternatively, if you want to add the LEFT and RIGHT to an existing rowset, you can achieve the same result by throwing them in with a collapsed colspan in between:

table {_x000D_
    border-collapse: collapse;_x000D_
}_x000D_
_x000D_
td {_x000D_
    padding: 20px; _x000D_
    border: 1px solid black; _x000D_
    text-align: center;_x000D_
}

<table>_x000D_
    <tbody>_x000D_
    <tr>_x000D_
        <td rowspan="3">LEFT</td>_x000D_
        <td colspan="4" style="padding: 0; border-bottom: solid 1px transparent;"></td>_x000D_
        <td rowspan="3">RIGHT</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
        <td> 1 </td>_x000D_
        <td> 2 </td>_x000D_
        <td> 3 </td>_x000D_
        <td> 4 </td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
        <td> 5 </td>_x000D_
        <td> 6 </td>_x000D_
        <td> 7 </td>_x000D_
        <td> 8 </td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
    </tr>_x000D_
    </tbody>_x000D_
</table>

<body>
<table>
<tr><td colspan="2" rowspan="2">1</td><td colspan="4">2</td></tr>
<tr><td>3</td><td>3</td><td>3</td><td>3</td></tr>
<tr><td colspan="2">1</td><td>3</td><td>3</td><td>3</td><td>3</td></tr>
</table>
</body>

You can use rowspan="n" on a td element to make it span n rows, and colspan="m" on a td element to make it span m columns.

Looks like your first td needs a rowspan="2" and the next td needs a colspan="4".

Use rowspan if you want to extend cells down and colspan to extend across.

Colspan and Rowspan A table is divided into rows and each row is divided into cells. In some situations we need the Table Cells span across (or merged) more than one column or row. In these situations we can use Colspan or Rowspan attributes.

Colspan The colspan attribute defines the number of columns a cell should span (or merge) horizontally. That is, you want to merge two or more Cells in a row into a single Cell.

<td colspan=2 > 

How to colspan ?

<html>
<body >
    <table border=1 >
        <tr>
            <td colspan=2 >
                Merged
            </td>
        </tr>
        <tr>
            <td>
                Third Cell
            </td>
            <td>
                Forth Cell
            </td>
        </tr>
    </table>
</body>
</html>

Rowspan The rowspan attribute specifies the number of rows a cell should span vertically. That is , you want to merge two or more Cells in the same column as a single Cell vertically.

<td rowspan=2 >

How to Rowspan ?

<html>
<body >
    <table border=1 >
        <tr>
            <td>
                First Cell
            </td>
            <td rowspan=2 >
                Merged
            </td>
        </tr>
        <tr>
            <td valign=middle>
                Third Cell
            </td>
        </tr>
    </table>
</body>
</html>

<style type="text/css">
     table { border:2px black dotted; margin: auto; width: 100%; }
    tr { border: 2px red dashed; }
    td { border: 1px green solid; }
</style>
<table>
    <tr>
        <td rowspan="2">x</td> 
        <td colspan="4">y</td>
    </tr>
    <tr>
        <td>I</td>
        <td>II</td>
        <td>III</td>
        <td>IV</td>
    </tr>
    <tr>
        <td>nothing</td>
        <td>1</td>
        <td>2</td>
        <td>3</td>
        <td>4</td>
    </tr>
</table>????????????????????????????????????????????????????????????????????????

I have used ngIf for one of my similar logic. it is as follows:

<table>
<tr *ngFor="let object of objectData; let i= index;">
<td *ngIf="(i%(object.rowSpan))==0" [attr.rowspan]="object.rowSpan">{{object.value}}</td>
</tr>
</table>

here, i'm getting rowspan value from my model object.