jquery live hover

Question

jQuery 1.4.1 now supports "hover" for live() events, but only with one event handler function:

$("table tr").live("hover",

function () {

});

Alternatively, you can provide two functions, one for mouseenter and one for mouseleave:

$("table tr").live({
    mouseenter: function () {

    },
    mouseleave: function () {

    }
});

$('.hoverme').live('mouseover mouseout', function(event) {
  if (event.type == 'mouseover') {
    // do something on mouseover
  } else {
    // do something on mouseout
  }
});

http://api.jquery.com/live/

.live() has been deprecated as of jQuery 1.7

Use .on() instead and specify a descendant selector

http://api.jquery.com/on/

$("table").on({
  mouseenter: function(){
    $(this).addClass("inside");
  },
  mouseleave: function(){
    $(this).removeClass("inside");
  }
}, "tr");  // descendant selector

As of jQuery 1.4.1, the hover event works with live(). It basically just binds to the mouseenter and mouseleave events, which you can do with versions prior to 1.4.1 just as well:

$("table tr")
    .mouseenter(function() {
        // Hover starts
    })
    .mouseleave(function() {
        // Hover ends
    });

This requires two binds but works just as well.

This code works:

    $(".ui-button-text").live(
        'hover',
        function (ev) {
            if (ev.type == 'mouseover') {
                $(this).addClass("ui-state-hover");
            }

            if (ev.type == 'mouseout') {
                $(this).removeClass("ui-state-hover");
            }
        });

WARNING: There is a significant performance penalty with the live version of hover. It's especially noticeable in a large page on IE8.

I am working on a project where we load multi-level menus with AJAX (we have our reasons :). Anyway, I used the live method for the hover which worked great on Chrome (IE9 did OK, but not great). However, in IE8 It not only slowed down the menus (you had to hover for a couple seconds before it would drop), but everything on the page was painfully slow, including scrolling and even checking simple checkboxes.

Binding the events directly after they loaded resulted in adequate performance.