My code is here: http://jsfiddle.net/PXU2w/8/
CODE
$('#navigation').hover(function() {
//Check if element with class 'author' exists, if so change it to 'authornew'
if ($('div.menu-description').length != 0) $('div.menu-description').removeClass('menu-description').addClass('menu-descriptionnew');
//Check if element with class 'authornew' exists, if so change it to 'author'
else if ($('div.menu-descriptionnew').length != 0) $('div.menu-descriptionnew').removeClass('menu-descriptionnew').addClass('menu-description');
});
});
What I want is when hovered on the background text color of the menu-description class should change to menu-descriptionnew.
You almost got it right, but you have a syntax error in the Javascript part.
The last closing brackets were not necessary.
http://jsfiddle.net/PXU2w/9/