var mydate = new Date();

  var week = ["星期日","星期一","星期二","星期三","星期四","星期五","星期六"];

  document.write("今天是：" + mydate.getFullYear()+ "年" + mydate.getMonth()+ "月" + mydate.getDate()+"日 "+week[mydate.getDay()]+"<br>"); 

  //成绩是一长窜的字符串不好处理，找规律后分割放到数组里更好操作哦

  var scoreStr = "小明:87;小花:81;小红:97;小天:76;小张:74;小小:94;小西:90;小伍:76;小迪:64;小曼:76";

  var myarr = scoreStr.split(";");

  var myarr1 = new Array();

  for(i=0;i<10;i++){

      myarr1[i] = myarr[i].substring(3);

  }

  //document.write(myarr1+"<br>");

  //从数组中将成绩撮出来，然后求和取整，并输出。

  var sum = 0;

  for(j=0;j<10;j++){

      sum = sum + parseInt(myarr1[j]);

  }

  ave = sum/10;

  document.write("平均成绩是：" + Math.round(ave));