Answers for "what is alt use for html"

alt html

<img src="img_girl.jpg" alt="Girl in a jacket" width="500" height="600">
<!--The alt tag is the alternative text displayed if an image cannot be loaded -->

alt meaning in html

If image has error being displayed, the alt text will be shown.
Screen readers can only read the alt text.
So describe your image in short under "alt" attribute.