jQuery not and classes

Question

Hi Guys,

I have 2 anchor links (a.selector) and when one is clicked it has a class applied to it of 'active-arrow' and the click also removes the class of the same name from the other anchor as well as lowering the opacity to 0.2.

I then want to have a fade effect when the user hovers over the anchor that doesn't have 'active-arrow' applied to it so that it goes to full opacity when mouseenters and back to 0.2 when mouseleaves.

The problem im having is that both .not and :not don't seem to be working as expected, the hover effect works but if I click on the anchor whilst hovering the 'active-arrow' class is applied but when mouseleaves the opacity is faded down to 0.2 again even though the 'active-arrow' class is applied. Also the hover then doesn't work for the other a link which has had 'active-arrow' removed.

Bit of a hard one to explain so heres some code that hopefully helps a bit.

*//If a.selector doesn't have the class 'active-arrow' then run the hoverFade function*
$("a.selector").not(".active-arrow").hoverFade();

//Functions for first element
        $('a.selector-1').click(function () {
            $('a.selector-2').removeClass('active-arrow'); //Remove background image from corresponding element
            $('ul#storage-items-2').fadeOut(1200).addClass('hide'); //Fade out then hide corresponding list
            $(this).addClass('active-arrow', 'fast'); //Add background image to current element
            $('ul#storage-items-1').removeClass('hide').fadeIn(1800); //Unhide and fade in the list
            $('a.selector-2').fadeTo(500, 0.2); //Fade corresponding element
            $(this).fadeTo(800, 1);//Fade this element to full opacity
        });

I only included the code for teh first anchor (a.selector-1) as the code for the second anchor is identical but just changes the class names to a.selector-2.

Also the hoverFade function is in a seperate file so we can re-use it.

    jQuery.fn.hoverFade = function() {
return this.each(function(){
        $(this).hover(
                function () {
                    $(this).fadeTo(500, 0.8);
            }, 
                function () {
                    $(this).fadeTo(500, 0.2);
        });
  });

}

Each anchor link fades in and fades out a UL as well.

Any help is most appreciated

Thanks

Giles

Answer 1

depending on where you call

$("a.selector").not(".active-arrow").hoverFade();

it will bind the fadeTo effect to all anchors regardless if they own the .active-arrow or not. You should rewrite the hoverFade() function like:

jQuery.fn.hoverFade = function() {
    return this.each(function(){
    if(!$(this).is('.active-arrow'){
       $(this).hover(
               function () {
                   $(this).fadeTo(500, 0.8);
           }, 
               function () {
                   $(this).fadeTo(500, 0.2);
       });
    }
});
}

Answer 2

This is a case where you want to use .live() or .delegate(), like this:

$("a.selector:not(.active-arrow)").live('mouseenter', function () {
  $(this).fadeTo(500, 0.8);
}).live('mouseleave', function () {
  $(this).fadeTo(500, 0.2);
});

If you use .delegate() the top line would look like this (ID = ID of shared parent to all these links):

$("#ID").delegate("a.selector:not(.active-arrow)", 'mouseenter', function () {

The reason what you currently have doesn't work is that it binds the event handler to the elements, the elements only had to match the selector you used when you found them for binding, once that happens, the .hover() mouseenter and mouseleave event handlers are bound on that element. The fact that the class changes later doesn't really matter, the handlers are there to stay.

Using the approach above, the events aren't actually on the elements directly, they sit on a parent, document in the case of .live() or #ID in the case of .delegate(). When the mouse events happen on an element they bubble up, and the parent sees them, checks if the selector that handler is for matches right then, and if so executes. This makes the class changing actually matter, as it's checked when the event happens, rather than when it was bound.