JavaScript基础实例:如何计算24点(3)

     n[3] = document.forms[0].fd.value;
     if ( n[0] > 0 && n[1] > 0 && n[2] > 0 && n[3] > 0 && n[0] < 14 && n[1] < 14 && n[2] < 14 && n[3] < 14 )
     {
      log("<font size=5><b>"+n[0]+", "+n[1]+", "+n[2]+", "+n[3]+"的24点答案：</b></font><br>");
      log("<input type='button' onclick='history.back(-1);' value=' 再来一次 '><br>");
      funMain();
      if ( counter == 0 )
      {
       log("没有答案！");
      }
     }
     else
     {
      alert("输入错误！");
     }
    }
   
    //主程序
    function funMain()
    {
        var m = new Array();
     //四种运算符
        m[0] = "+";
        m[1] = "-";
        m[2] = "*";
        m[3] = "/";
       
     //11种表达式
        var exp1 = "a m1 b m2 c m3 d;";
        var exp2 = "(a m1 b) m2 c m3 d;";
        var exp3 = "(a m1 b m2 c) m3 d;";
        var exp4 = "((a m1 b) m2 c) m3 d;";
        var exp5 = "(a m1 (b m2 c)) m3 d;";
        var exp6 = "a m1 (b m2 c) m3 d;";
        var exp7 = "a m1 (b m2 c m3 d);";
        var exp8 = "a m1 ((b m2 c) m3 d);";