Converting width from percentage to pixels

Question

I have a table inside a <div>:

<div id="fixeddiv">
    <table id="fixedtable">
        <tr class="firstrow">
            <td class="td11"></td>
            <td class="td12"></td>
            <td class="td13"></td>
        </tr>

        <tr class="secondrow">
            <td class="td21" style="width:10%"></td>
            <td class="td22" style="width:20%"></td> 
            <td class="td23" style="width:70%"></td>
        </tr>
    </table>
</div>

CSS:

#fixeddiv
{
    overflow:auto;
    margin:0px;
    padding:0px;
    position: relative;
    text-align:left;
    width: 48%;
}

#fixedtable
{
    background-color: White;
    border-spacing:0px;
    cursor: pointer;
    width: 100%;
    height: 100%;
    font-family: Calibri !important;
    color: Black;
    font-size: 14px;
}

.firstrow
{
    position: absolute;
    margin: 0px;
    left: 0;
    top: 0;
    background: url(../Content/Images/header.jpg) repeat-x center top;
    color: White;
    font-weight: bold;
    text-align: center;

}
#fixedtable tr td
{
    padding: 5px !important;
    border: 1px solid #FFFFFF;
    text-align: center;
}

I am calculating the width of td21 with $('.td21').width() and assigning the width to td11 like $('td11').width($('.td21').width()).

The problem is that the widths applying are not same, they vary by 1px and I could not find how this 1px difference occur. The .td21 width is 1px greater than .td11.

Can any one please help me to find the solution?

Answer 1

<div id="div-1" style="width: 1000px;">
    <div id="div-2" style="width: 10%;"></div>
</div>

<script language="javascript">                
    var percents = parseInt(document.getElementById("div-2").style.width);
    var parentWidth = parseInt(document.getElementById("div-1").style.width);
    var pixels = parentWidth*(percents/100);
    alert(pixels); // will print "100"
</script>