Why return this.each(function()) in jQuery plugins?
Solution 1:
When you filter elements with a selector ($('.myclass')), it can match more than only one element.
With each, you iterate over all matched elements and your code is applied to all of them.
Solution 2:
jQuery supports "chainable methods", which means that most jQuery functions should return this. .each() returns this, and if you want $('selector').yourPlugin().css(...) to work, you should return this.