计算任意日期所在周起止日期

function showDate(date)
{
    var now = date ? new Date(date) : new Date();
    var start = date ? new Date(date) : new Date();
    var end = date ? new Date(date) : new Date();
    var n = now.getDay();
    var result = {};
    
    start.setDate(now.getDate() - n + 1);
    end.setDate(now.getDate() - n + 7);
    
    start = start.getFullYear() + "-" + toDouble(start.getMonth() + 1) + "-" + toDouble(start.getDate());
    end = end.getFullYear() + "-" + toDouble(end.getMonth() + 1) + "-" + toDouble(end.getDate());
    
    result.start = start;
    result.end = end;
    
    return result;
}

function toDate(date)
{
    var aDate = date.split("-");
    var result = new Date(aDate[0], (aDate[1] - 1), aDate[2]);
    
    return result;
}

function toDouble(num)
{
    return num < 10 ? '0' + num : num;    
}