// 计算系统当前是星期几

 var str ="";

 var week =new Date().getDay();

 if (week ==) {

 str ="今天是星期日";

 } elseif (week ==) {

 str ="今天是星期一";

 } elseif (week ==) {

 str ="今天是星期二";

 } elseif (week ==) {

 str ="今天是星期三";

 } elseif (week ==) {

 str ="今天是星期四";

 } elseif (week ==) {

 str ="今天是星期五";

 } elseif (week ==) {

 str ="今天是星期六";

 }

 // 或者更好一些

 var str1 ="今天是星期";

 var week =new Date().getDay();

 switch (week) {

 case0 :

 str1 +="日";

 break;

 case1 :

 str1 +="一";

 break;

 case2 :

 str1 +="二";

 break;

 case3 :

 str1 +="三";

 break;

 case4 :

 str1 +="四";

 break;

 case5 :

 str1 +="五";

 break;

 case6 :

 str1 +="六";

 break;

 }

 alert(str);

 alert(str1);

 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);

 // 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());