An id on a <main> tag assigns an identifier to the element.
The identifier must be unique across the page.
An id attribute on a <main> element.
<main id="impressionism">
<b>Impressionism</b> is a 19th-century art movement
characterized by relatively small brush strokes,
emphasis on accurate depiction of light, ordinary
subject matter, and unusual visual angles.
Impressionism originated with a group of
Paris-based artists whose independent exhibitions
brought them to prominence in the 1870s and 1880s.
</main>
The id attribute assigns an identifier to the <main> element.
The id allows JavaScript to easily access the <main> element.
It is also used to point to a specific id selector in a style sheet.
Tip: id is a global attribute that can be applied to any HTML element.
<main id="identifier" />
| Value | Description |
|---|---|
| identifier | A unique alphanumeric string. The id value must begin with a letter ([A-Za-z]) and may be followed by any number of letters, digits ([0-9]), hyphens (-), underscores (_), colons (:), and periods (.). |
A <main> element with a unique id.
Clicking the button will display a character count for the text in the element.
<main id="mymain">
<b>Impressionism</b> is a 19th-century art movement
characterized by relatively small brush strokes,
emphasis on accurate depiction of light, ordinary
subject matter, and unusual visual angles.
Impressionism originated with a group of
Paris-based artists whose independent exhibitions
brought them to prominence in the 1870s and 1880s.
</main>
<br />
<button onclick="show();">Show character count</button>
<script>
let show = () => {
let content = document.getElementById("mymain").innerHTML;
let count = content.length;
alert("Count = " + count);
}
</script>
The id attribute assigns a unique identifier for the <main> element.
Clicking the button calls JavaScript which locates the <main> using the id.
It then counts the number of characters in the <main> content and displays it in an alert box.
Here is when id support started for each browser:
 Chrome
|
6.0 | Sep 2010 |
 Firefox
|
4.0 | Mar 2011 |
 IE/Edge
|
12.0 | Jul 2015 |
 Opera
|
11.1 | Mar 2011 |
 Safari
|
5.0 | Jun 2010 |
Back to <main>
