now = new Date() //定义新对象，new具有Date的性质
if (now.getDay() == 5) document.write("星期五")

if (now.getDay() == 6) document.write("星期六")

if (now.getDay() == 0) document.write("星期日")

if (now.getDay() == 1) document.write("星期一")

if (now.getDay() == 2) document.write("星期二")

if (now.getDay() == 3) document.write("星期三")

if (now.getDay() == 4) document.write("星期四")