Question

Why does onmouseover run multiple times while I hover over one element?

I’m trying to run a simple animation when the user hovers over an icon but it runs multiple times.

I’m testing it here:

http://lujanventas.com/test.php

Anyway, any ideas on how to fix it? maybe using a listener instead?

This is the javascript running onmouseover:

function upIcon(n) {
    console.log("Mouseover icon: " + n);
    $('#icon' + n).animate({ backgroundPositionY : "-=15px" }, 200 );
    $('#icon' + n).animate({ backgroundPositionY : "+=15px" }, 200 );
    }

Answer 1

Try using mouseenter and mouseleave instead of mouseover and mouseout. The former fires only when the cursor enters the region of the element and the latter fires when the cursor moves between descendants as well.

I added this code to your page via my console and it worked as expected:

//bind an event handler to each nav element for the mouseenter event
$('.categoryButtons').children().bind('mouseenter', function () {

    //call the `upIcon` function with the index of the current element
    upIcon(($(this).index() + 1));
});

I also removed the inline onmouseover code for each nav item.

Update

You can use your existing function a bit differently and not use the anonymous function for your event handler (notice the function chaining to avoid duplicate selections):

function upIcon(event) {
    var n = ($(this).index() + 1);
    $('#icon' + n).animate({ backgroundPositionY : "-=15px" }, 200 ).animate({ backgroundPositionY : "+=15px" }, 200 );
}

$('.categoryButtons').children().bind('mouseenter', upIcon);

When you reference an existing function as the event handler, it gets passed the event object like any other event handler and you can also use this to refer to the element on which the event was triggered.