The text alternative for an image must be no more than 100 characters in length.
A text alternative should summarize the purpose of an image as succinctly as possible for people with visual impairments.
Overly long text alternatives can reduce usability by increasing the time it takes to read a web page and understand the significance of the included images.
An image with a text alternative that is an empty string (e.g. alt="") is ignored by assistive technologies, and indicates that it is being used for purely decorative, spacing or stylistic purposes rather than for meaningful content.
A text alternative (e.g. in English and many other Western languages) should describe the purpose of an image as succinctly as possible (preferably with no more than 100 characters).
If a text alternative requires more than 100 characters, consider using the aria-describedby, title or longdesc attribute for a longer, more detailed description of the image, along with shortening the text alternative content.
Information about the element associated with the result.
The information typically includes the tag name, accessible name or other information related to the rule requirements.
"Page" means that the result applied to the page. For example, the rule "One main landmark on the page" is a page level rule.
The element position is based on the DOM order of elements in the page.
The element position maybe useful in helping to locate a specific element on the page evaluated (e.g smaller numbers are typically toward the beginning of a page and larger numbers typically toward the end of a page).
Element position 1 is the first element.
The highest element position is the last element.
Element position values for most rule/page results will not be consecutive since a rule only applies to a sub set of elements found on a page.