// 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";
switch (week) {
        case 0 :
                str += "日";
                break;
        case 1 :
                str += "一"case 2 :
                str += "二"case 3 :
                str += "三"case 4 :
                str += "四"case 5 :
                str += "五"case 6 :
                str += "六";
}
alert(str);

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