firefox's strange behavior using jQuery animate method and absolute position

Question

I have a problem when I'm using jQuery's(jQuery1.9.1) animate method. Here is my code in jsfiddle: http://jsfiddle.net/AySas/3/ I want to make the div wider using the relative percentage, ie:

html:
<div id="h_divCenter">
    <div id="h_divIETodos" >
        <div id="h_divIIEodoList" class="quadContent">
            <ul id="h_ulIETodoList">
                <li>itemC 3</li>
            </ul>
        </div>
    </div>

css:
#h_divCenter {
    position:absolute;
    top:0;
    left:20px;
    right:100px;
    bottom:0;
    margin: 5px;
    background: #0FF;
}
.quadContent {
    position: absolute;
    top: 41px;
    bottom: 2px;
    padding: 1px 1% 2px 1%;
    width: 98%;

}
#h_ulIETodoList,#h_ulIUTodoList,#h_ulUETodoList,#h_ulUUTodoList {
    width: 100%;
    height: 100%;
    list-style-type: none;
    overflow: auto;
}
 #h_divIETodos {
    position: absolute;
    margin: 2px;
    top: 0;
    left: 0;
    right: 50%;
    bottom: 50%;
    color: #DE3C3C;
    border: 1px solid #DE3C3C;
     -webkit-box-shadow: 0px 0px 10px #DE3C3C;
     -moz-box-shadow: 0px 0px 10px #DE3C3C;
     box-shadow: 0px 0px 10px #DE3C3C;
 }


javascript:
$('#btnTest').on("click", function(){
    $("#h_divIETodos").animate({
        right: "+=20%"
    },500);
});

And this div has a absolute position and I have set the top,right,bottom,left properties of css. It works fine in chrome. But in firefox, you can see the right edge of the div cannot move by "20%". Has someone else encountered with the similar problem before? I really appreciate your help. Many thanks!

Answer 1

You can work with calculated pixels instead. Works as expected.

jsFiddle Demo

$('#btnTest').on("click", function(){

        $("#h_divIETodos").animate({

            right: "+=" + ($(this).parent().width() * 0.2) + "px"
        },500);
    });