Puzzle 7.6.5...1

var MyArray = [8,7,6,5,4,3,2,1],
    OpeArray = [0,0,0,0,0,0],
    StrArray = ["-","+","*","/"],
    ResultArray = [];
    last_str = "";
var count = 0;

function Insert(a,b,position) {
    return a.substr(0, position) + b + a.substr(position);
}


function Calculate() {
    var st = "", res = 0;
  for (var i = 0; i < MyArray.length - 1; i++) {
    st += MyArray[i] + OpeArray[i];
  }
  st += MyArray[i]
  var st2 = st;
  var t = 0;
  for (var i = 0; i < st.length; i++) {
      if (parseInt(st[i]) > 0) {
        st2 = Insert(st2,"(",i);
      } else {continue}
      for (var j = i + 1; j < st2.length; j++) {
            var st3 = st2;
          if (parseInt(st2[j]) > 0) {
            st3 = Insert(st3,")",j+1);
            t += 1;

            } else { continue }
          //document.write(st3 + "<br>");
          res = eval(st3);
          if (res >= 2015) {
            //document.write(st3 + " = " + res + "<br>");
            if (ResultArray.indexOf(st3) === -1){
                ResultArray.push(st3);
            }

          }
          st3 = st2;
    }
    st2 = st;
  }
  //res = eval(st);
  last_str = st;
  //if (res > 1000) {
  //    document.write(st + " = " + res + "<br>");
  //}
}

function WriteArray() {
  Calculate();
}

function Try(i) {
  for (var j = 0; j < 4; j++) {
    OpeArray[i] = StrArray[j];
    if (i === MyArray.length - 1) {
      Calculate();
      count = count + 1;
    } else {
        Try(i+1);
    }
  }
}

Try(0);
for (var i = 0; i < ResultArray.length; i++) {
    var result = eval(ResultArray[i]);
    document.write(ResultArray[i] + " = " + result + "<br>");
}
document.write("Done!");