// 计算系统当前是星期几
var str = "今天是星期" + "日一二三四五六".charat(new date().getday());

var a = new array("日", "一", "二", "三", "四", "五", "六");
var week = new date().getday();
var str = "今天是星期"+ a[week];
alert(str);

var str = "今天是星期";
var week = new date().getday();
switch (week) {
  case 0 :
    str1 += "日";
    break;
  case 1 :
    str1 += "一";
    break;
  case 2 :
    str1 += "二";
    break;
  case 3 :
    str1 += "三";
    break;
  case 4 :
    str1 += "四";
    break;
  case 5 :
    str1 += "五";
    break;
  case 6 :
    str1 += "六";
    break;
}
alert(str);

var str = "";
var week = new date().getday();
if (week == 0) {
  str = "今天是星期日";
} else if (week == 1) {
  str = "今天是星期一";
} else if (week == 2) {
  str = "今天是星期二";
} else if (week == 3) {
  str = "今天是星期三";
} else if (week == 4) {
  str = "今天是星期四";
} else if (week == 5) {
  str = "今天是星期五";
} else if (week == 6) {
  str = "今天是星期六";
}
alert(str);