Question: Sometimes I see constructs like [`$('<img/>')`](https://stackoverflow.com/questions/6124409/image-size-before-is-in-dom). How is `$('<img/>')` different from `$('img')` and where can I read more about this?

I tried looking at [jQuery Selectors](http://api.jquery.com/category/selectors/) but found nothing related to this format.

Answer: 
The jQuery function is overloaded to construct new jQuery elements when passed a string that looks like HTML. From the [docs](http://api.jquery.com/jQuery/#jQuery2):

> 
> If a string is passed as the parameter to $(), jQuery examines the
>  string to see if it looks like HTML (i.e., it starts with `<tag ... >`).
>  If not, the string is interpreted as a selector expression, as
>  explained above. But if the string appears to be an HTML snippet,
>  jQuery attempts to create new DOM elements as described by the HTML.
>  Then a jQuery object is created and returned that refers to these
>  elements.
> 
> 
>
`$('<img/>')` **creates** an image, whereas `$('img')` selects all currently existing images.