jQuery.fx.prototype.custom uses jQuery.timers.push(t) == 1 as a guard condition for the setInterval call, which is not robust enough. In the test case, stop, which empties jQuery.timers, is called before animate so that the check will pass even though there is already an active interval. This causes a leak because timerId gets overwritten every time and there is no way to clearInterval.

IE issue:

If a user creates a form with inputs named "action" or "method" jQuery fails when attempting to update the method or action attributes of the form object. This becomes a problem for the Form Plugin which tries to do the following when uploading files:

$form.attr({
    target:   id,
    method:   'POST',
    action:   opts.url
});

In IE, this fails in jQuery 1.3.1 at line 985 (attr fn):

elem[ name ] = value;

Turns out that this also fails in jQuery 1.2.6 but not in jQuery 1.2.3.

A test page is available here:

​http://jquery.malsup.com/form/action.html

xhtml snippet: <p id="bpUsername"><input name="bpUsername" type="text"/></p>

jquery snippet: alert($("#bpUsername input").attr("value"));

The value is returned correctly in 1.2.6

Upgrading to 1.3.1 resulted in a returned value of "undefined"