$.get('CaculateWeekDay', { y: 2016, m: 8, d: 9 }, function (result) {
alert(result);
})

/// <summary>
/// 计算具体某个日期是星期几
/// </summary>
/// <param name="y">年</param>
/// <param name="m">月</param>
/// <param name="d">日</param>
/// <returns></returns>
public string CaculateWeekDay(int y, int m, int d) 
{
if (m == 1 || m == 2) 
{
m += 12;
y--;
}
int week = (d + 2 * m + 3 * (m + 1) / 5 + y + y / 4 - y / 100 + y / 400) % 7;
string weekstr = "";
switch (week)
{
case 0: weekstr = "星期一"; break;
case 1: weekstr = "星期二"; break;
case 2: weekstr = "星期三"; break;
case 3: weekstr = "星期四"; break;
case 4: weekstr = "星期五"; break;
case 5: weekstr = "星期六"; break;
case 6: weekstr = "星期七"; break;
}
return weekstr;
}