Edit in JSFiddle

$(document).ready(function()
{
    $(':input[type=textbox]').css("text-align", "right").attr("maxlength", "11");
    TextBoxNumberToAddComma();
});

function TextBoxNumberToAddComma()
{
    $(':input[type=textbox]').each(function(i, item)
    {
        $(item).focus(function()
        {
            //當獲得focus時，要把千分位給拿掉
            $(this).val(RemoveComma($(this).val()));
            $(this).select();
        })
        .blur(function()
        {
            //限制輸入長度
            TextAreaLength(this, 14);
    
            //加千分位
            AdjustComma(this, 11);
        });
    });
}

//數字處理為有千分位
function AppendComma(n)
{
    if (!/^((-*\d+)|(0))$/.test(n))
    {
        var newValue = /^((-*\d+)|(0))$/.exec(n);
        if (newValue != null)
        {
            if (parseInt(newValue, 10))
            {
                n = newValue;
            }
            else
            {
                n = '0';
            }
        }
        else
        {
            n = '0';
        }
    }

    if (parseInt(n, 10) == 0)
    {
        n = '0';
    }
    else
    {
        n = parseInt(n, 10).toString();
    }
    
    n += '';
    var arr = n.split('.');
    var re = /(\d{1,3})(?=(\d{3})+$)/g;
    return arr[0].replace(re, '$1,') + (arr.length == 2 ? '.' + arr[1] : '');
}

//將有千分位的數值轉為一般數字
function RemoveComma(n)
{
    return n.replace(/[,]+/g, '');
}

//調整千分位
function AdjustComma(item, length)
{
    var originalValue = $.trim($(item).val()).length > length 
        ? $.trim($(item).val()).substr(0, length) 
        : $.trim($(item).val());
    
    $(item).val(AppendComma(originalValue));
}

//動態調整輸入欄位的長度
function TextAreaLength(item, length) 
{
    if (item.value.length > length) 
    {
        item.value = item.value.substring(0, length);
    }
}        

TextBox MaxLength: 11
<br/>
<input type="textbox" id="textNumber" name="textNumber" />