jQuery class selector doesn't work and id selector works only with “body”

Question

I\'m trying to apply CSS values with jquery but class selector or id selector does not not work for some reason.

Here is my fiddle:

As you can see nothing happen

Answer 1

Id selectors are prefixed with #:

$("#kitten").css("background-position", x + "px 0");

A class selector would be prefixed with a ., for instance if kitten were a class:

$(".kitten").css("background-position", x + "px 0");

When you use the body selector you are using a tag selector which has no prefix.

$("input"); //selects all input tags

For most basic selectors, just follow CSS selector syntax.