The alt attribute is supposed to be an alternative for the image, usually stating its purpose.

An alternative alt attribute value would be "The Danish flag".

All images that are used to illustrate content include the alt attribute to provide descriptive text alternatives.

The alt attribute is commonly, but incorrectly, referred to as the "alt tag".

In this case, if the image truly does not add to the content, then a blank alt attribute should be included in the form of .

Safari and Google Chrome, on the other hand, do not display the alt attribute at all.)

Here is an image for which the alt attribute is "In the sky flies a red flag with a white cross whose vertical bar is shifted toward the flagpole."

Search engine optimization encompasses both "on page" factors (like body copy, title elements, H1 heading elements and image alt attribute values) and Off Page Optimization factors (like anchor text and PageRank).

The alt attribute is used in HTML and XHTML documents to specify alternative text (alt text) that is to be rendered when the element to which it is applied cannot be rendered.

Unrelated hidden text is disguised by making it the same color as the background, using a tiny font size, or hiding it within HTML code such as "no frame" sections, alt attributes, zero-sized DIVs, and "no script" sections.

The most common way around these problems is to use images of text, which can then be rotated and transformed in an image editor at will, and to represent the text in those images with the alt attribute so that search engines and text-only browsers can read it properly.