The declaration order affects the each column respectively(just like if you define col for first/second column it show its affect only for first/second column.).This order can be affected by the use of the "span" attribute. This attribute can be used in this tag to affect more than one column with the same declaration. col tag defines in the colgrp tag in table tag.
The most common attributes available for this tag are purely presentational (align, valign, width, char and charoff).We may also use css properties for same work. The <col> tag has no end tag In HTML,while has properly closed tag in XHTML.
You can understand use of <col> tag by a simple example:-
<!DOCTYPE html>
<html>
<body>
<p>This example shows a colgroup that has four columns of different widths:</p>
<table border="1">
<colgroup span="3">
<col width="50" background: red;></col>
<col width="100" background: green;></col>
<col width="150" background: yellow;></col>
<col width="50" background: pink;></col>
</colgroup>
<tr>
<td>col 1</td>
<td>col 2</td>
<td>col 3</td>
<td>col 4</td>
</tr>
</table>
</body>
</html>
Result:-
col 1 | col 2 | col 3 | col 4 |
The following attributes can be set for the <col> tag:-
<br> Tag Attributes
<br clear="none|left|right|all">Attribute | Value | Description |
---|---|---|
align | left | Data is aligned to the left.It is default value. |
center | Data is aligned to center | |
right | Data is aligned to right | |
justify | Data is justified. | |
char | The text is aligned to a specific character | |
charoff | number | number of characters the content will be aligned from the character specified by the char attribute.Not supported in HTML5. |
span | number | number of columns a <col> element should span |
valign | top | Data is aligned to the top. |
middle | Data is vertically centered. | |
bottom | aligned to the bottom. | |
baseline | All the cells in a row with this alignment should have their first text line on a common baseline. | |
width | % pixels |
width of a <col> element |
Conclusion:--
<col> tag का उपयोग colgrp में प्रत्येक column की अलग-अलग properties परिभाषित करने में किया जाता है आपको इस tag को तब use करना चाहिए जब प्रत्येक कॉलम के लिए आपको भिन्न-भिन्न properties use करनी हो अन्यथा सभी columns को समान properties देने के लिए colgrp tag में properties define करनी चाहिए.