星期几的不同脚本写法(推荐)和JS年月日格式

1、使用 if 语句：

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";
}

2、使用switch case 语句：

var str1 = "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(str1);

3、神器，一句话解决

var str = "今天是星期" + "日一二三四五六".charAt(new Date().getDay());
alert(str);

4、JS年月日(2016-06-12)

var nowDate = new Date();
var year = nowDate.getFullYear();
var month = nowDate.getMonth() + 1 < 10 ? "0" + (nowDate.getMonth() + 1) : nowDate.getMonth() + 1;
var day = nowDate.getDate() < 10 ? "0" + nowDate.getDate() : nowDate.getDate();
var dateStr = year + "-" + month + "-" + day;
alert(dateStr);