diff --git a/fortune_generator/fortune.js b/fortune_generator/fortune.js
index 7c4540f..898d8ad 100644
--- a/fortune_generator/fortune.js
+++ b/fortune_generator/fortune.js
@@ -31,12 +31,14 @@ const title = `<span style='font-size: 8vmin; color: #000000CC;'><b>今日運勢
 const allGood = `<span style='font-size: 6vmin; color: #000000bf;'><b>萬事皆宜<b></span>`;
 const allBad = `<span style='font-size: 6vmin; color: #e74c3c;'><b>諸事不宜<b></span>`;
 
+// date
 const d = new Date();
 const date = d.getDate();
 const day = d.getDay();
 const month = d.getMonth() + 1;
 const year = d.getFullYear();
 
+// before press button
 const showMonth = `<span style='font-size: 10vmin; color: #054310C9; -webkit-writing-mode: vertical-lr;'><b>${chineseMonth[month - 1] + "月"}<b></span>`;
 const showDate = `<span style='font-size: 25vmin; color: #054310C9;'><b>${("0" + date).substr(-2)}<b></span>`;
 const showDay = `<span style='font-size: 10vmin; color: #054310C9; -webkit-writing-mode: vertical-lr; margin-right: 10%;'><b>${"星期" + week[day]}<b></span>`;
@@ -54,6 +56,7 @@ function Appear() {
   $('#weekday').html('');
   $('#btn').html('打卡成功');
 
+  // transform ip to four numbers
   let p = 0;
   let num = [0, 0, 0, 0];
   for(let i = 0; i < 14; i++) {
@@ -63,12 +66,14 @@ function Appear() {
     }
     num[p] = num[p] * 10 + parseInt(ip[i]);
   }
-
+  
+  // some lengths
   const goodLen = goodFortunes.length;
   const badLen = badFortunes.length;
   const statusLen = fortuneStatus.length;
   const specialLen = special_events.length;
   
+  // check if there is special event to today
   let = special_events_index = 0;
   for(let i = 0; i < specialLen; i++){
     if(special_events[i].year == year && special_events[i].month == month && special_events[i].date == date){
@@ -78,6 +83,7 @@ function Appear() {
     }
   }
 
+  // TODO: improve the hash process
   let hashDate = Math.round(Math.log10(year * ((month << (Math.log10(num[3]) + 1)) * (date << Math.log10(num[2])))));
   let seed1 = (num[0] >> hashDate) * (num[1] >> Math.min(hashDate, 2)) + (num[2] << 1) * (num[3] >> 3) + (date << 3) * (month << hashDate) + year;
   let seed2 = (num[0] << (hashDate + 2)) * (num[1] << hashDate) + (num[2] << 1) * (num[3] << 3) + (date << (hashDate - 1)) * (month << 4) + year >> hashDate;
@@ -87,7 +93,7 @@ function Appear() {
   
   if(special){
     status_index = special_events[special_events_index].status_index;
-    special_status = `<span style='font-size: 12vmin; color: ${textColor[status_index]};'><b>§ ${fortuneStatus[status_index]} §</b></span>`;
+    let special_status = `<span style='font-size: 12vmin; color: ${textColor[status_index]};'><b>§ ${fortuneStatus[status_index]} §</b></span>`;
     $('#ip-to-fortune').html(special_status);
   }
   else{
@@ -96,18 +102,27 @@ function Appear() {
 
   let l_1_event, l_1_desc, l_2_event, l_2_desc, r_1_event, r_1_desc, r_2_event, r_2_desc;
   let l1, l2, r1, r2;
+
+  // make sure the events won't collide
   let set = new Set();
-  l1 = seed1 % goodLen;
+  l1 = (seed1 % goodLen + goodLen) % goodLen;
   set.add(goodFortunes[l1].event);
-  l2 = ((seed1 << 1) + date + goodLen) % goodLen;
-  while(set.has(goodFortunes[l2].event)) l2 = (l2 + 1) % goodLen;
+  l2 = (((seed1 << 1) + date) % goodLen + goodLen) % goodLen;
+  while(set.has(goodFortunes[l2].event)){
+    l2 = (l2 + 1) % goodLen;
+  } 
   set.add(goodFortunes[l2].event);
-  r1 = ((seed1 >> 1) + (d.getMonth() << 3)) % badLen;
-  while(set.has(badFortunes[r1].event)) r1 = (r1 + 2) % badLen;
+  r1 = (((seed1 >> 1) + (d.getMonth() << 3)) % badLen + badLen) % badLen;
+  while(set.has(badFortunes[r1].event)){
+    r1 = (r1 + 2) % badLen;
+  } 
   set.add(badFortunes[r1].event);
   r2 = ((((((seed1 << 3) + (d.getFullYear() >> 5) * (date << 2)) % badLen) * seed2) >> 6) % badLen + badLen) % badLen;
-  while(set.has(badFortunes[r2].event)) r2 = (r2 + 1) % badLen;
+  while(set.has(badFortunes[r2].event)){
+    r2 = (r2 + 1) % badLen;
+  } 
 
+  // organize the stuffs below this line... 
   l_1_event = `<span style='font-size: 5.6vmin; color: #e74c3c;'><b>宜: </b>${goodFortunes[l1].event}</span>`;
   l_1_desc = `<span style='font-size: 3.5vmin; color: #7f7f7f;'>${goodFortunes[l1].description}</span>`;
   l_2_event = `<span style='font-size: 5.6vmin; color: #e74c3c;'><b>宜: </b>${goodFortunes[l2].event}</span>`;