前提・実現したいこと

jsで画像を使用したカウントダウンタイマーを作成しています。
ブラウザの横幅によって表示サイズを変更するためレスポンシブで作成し、PCでは問題なく動作、表示切り替えできるのですが、スマートフォン時にうまくいきません。
表示自体はできているのですが、読み込み直後はスクロールさせないとタイマーが動作しません。読み込み後スクロールしなくても動くようにしたしです。

該当のソースコード

下記サイトを参考にさせていただいています。
http://cly7796.net/wp/javascript/countdown-image-timer/

JavaScript
1$(function(){
2  $(window).on('load resize', function() {
3
4      var windowWidth = window.innerWidth;
5
6      if (windowWidth > 768) {
7        if (window.name != "pc"){
8          location.reload();
9          window.name = "pc";
10        }
11      // ********** PCの記述 ********** //
12    var gYear = 2020, // 年
13        gMonth = 9, // 月
14        gDay = 9, // 日
15        gHour = 0, // 時
16        gMinute = 0, // 分
17        gSecond = 0; // 秒
18
19    var goal = new Date(gYear, gMonth-1, gDay, gHour, gMinute, gSecond);
20
21    var numHeight = 118;
22
23    var currentTime, period,
24        cDay, ｃDayHundred, ｃDayTen, ｃDayOne,
25        cHour, ｃHourTen, ｃHourOne,
26        cMinute, cMinuteTen, cMinuteOne,
27        cSecond, cSecondTen, cSecondOne,
28        cFlame,
29        insert = "";
30
31    var dayTen = document.getElementById('day-ten'),
32        dayOne = document.getElementById('day-one'),
33        hourTen = document.getElementById('hour-ten'),
34        hourOne = document.getElementById('hour-one'),
35        minuteTen = document.getElementById('minute-ten'),
36        minuteOne = document.getElementById('minute-one'),
37        secondTen = document.getElementById('second-ten'),
38        secondOne = document.getElementById('second-one');
39
40        function countdown() {
41
42            currentTime = new Date();
43            period = goal.getTime() - currentTime.getTime();
44
45            if(period >= 0) {
46                cDay = Math.floor(period / (1000 * 60 * 60 * 24));
47                period -= (cDay * (1000 * 60 * 60 * 24));
48                cDay = String(cDay);
49                while(cDay.length < 4) {
50                    cDay = '0' + cDay;
51                }
52                dayTen.style.top = (- cDay.substr(2, 1) * numHeight) + 'px';
53                dayOne.style.top = (- cDay.substr(3, 1) * numHeight) + 'px';
54
55                cHour = Math.floor(period / (1000 * 60 * 60));
56                period -= (cHour * (1000 * 60 * 60));
57                cHour = String(cHour);
58                while(cHour.length < 2) {
59                    cHour = '0' + cHour;
60                }
61                hourTen.style.top = (- cHour.substr(0, 1) * numHeight) + 'px';
62                hourOne.style.top = (- cHour.substr(1, 1) * numHeight) + 'px';
63
64                cMinute = Math.floor(period / (1000 * 60));
65                period -= (cMinute * (1000 * 60));
66                cMinute = String(cMinute);
67                while(cMinute.length < 2) {
68                    cMinute = '0' + cMinute;
69                }
70                minuteTen.style.top = (- cMinute.substr(0, 1) * numHeight) + 'px';
71                minuteOne.style.top = (- cMinute.substr(1, 1) * numHeight) + 'px';
72
73                cSecond = Math.floor(period / (1000));
74                period -= (cSecond * (1000));
75                cSecond = String(cSecond);
76                while(cSecond.length < 2) {
77                    cSecond = '0' + cSecond;
78                }
79                secondTen.style.top = (- cSecond.substr(0, 1) * numHeight) + 'px';
80                secondOne.style.top = (- cSecond.substr(1, 1) * numHeight) + 'px';
81
82                setTimeout(countdown, 10);
83
84            } else {
85            }
86        }
87      countdown();
88      } else {
89        if (window.name != "sp"){
90          location.reload();
91          window.name = "sp";
92        }
93        // ********** SPの記述 ********** //
94    var gYear = 2020, // 年
95        gMonth = 9, // 月
96        gDay = 9, // 日
97        gHour = 0, // 時
98        gMinute = 0, // 分
99        gSecond = 0; // 秒
100
101    var goal = new Date(gYear, gMonth-1, gDay, gHour, gMinute, gSecond);
102
103    var numHeight = 11.33333;
104
105    var currentTime, period,
106        cDay, ｃDayHundred, ｃDayTen, ｃDayOne,
107        cHour, ｃHourTen, ｃHourOne,
108        cMinute, cMinuteTen, cMinuteOne,
109        cSecond, cSecondTen, cSecondOne,
110        cFlame,
111        insert = "";
112
113    var dayTen = document.getElementById('day-ten'),
114        dayOne = document.getElementById('day-one'),
115        hourTen = document.getElementById('hour-ten'),
116        hourOne = document.getElementById('hour-one'),
117        minuteTen = document.getElementById('minute-ten'),
118        minuteOne = document.getElementById('minute-one'),
119        secondTen = document.getElementById('second-ten'),
120        secondOne = document.getElementById('second-one');
121
122        function countdown() {
123
124            currentTime = new Date();
125            period = goal.getTime() - currentTime.getTime();
126
127            if(period >= 0) {
128                cDay = Math.floor(period / (1000 * 60 * 60 * 24));
129                period -= (cDay * (1000 * 60 * 60 * 24));
130                cDay = String(cDay);
131                while(cDay.length < 4) {
132                    cDay = '0' + cDay;
133                }
134                dayTen.style.top = (- cDay.substr(2, 1) * numHeight) + 'vw';
135                dayOne.style.top = (- cDay.substr(3, 1) * numHeight) + 'vw';
136
137                cHour = Math.floor(period / (1000 * 60 * 60));
138                period -= (cHour * (1000 * 60 * 60));
139                cHour = String(cHour);
140                while(cHour.length < 2) {
141                    cHour = '0' + cHour;
142                }
143                hourTen.style.top = (- cHour.substr(0, 1) * numHeight) + 'vw';
144                hourOne.style.top = (- cHour.substr(1, 1) * numHeight) + 'vw';
145
146                cMinute = Math.floor(period / (1000 * 60));
147                period -= (cMinute * (1000 * 60));
148                cMinute = String(cMinute);
149                while(cMinute.length < 2) {
150                    cMinute = '0' + cMinute;
151                }
152                minuteTen.style.top = (- cMinute.substr(0, 1) * numHeight) + 'vw';
153                minuteOne.style.top = (- cMinute.substr(1, 1) * numHeight) + 'vw';
154
155                cSecond = Math.floor(period / (1000));
156                period -= (cSecond * (1000));
157                cSecond = String(cSecond);
158                while(cSecond.length < 2) {
159                    cSecond = '0' + cSecond;
160                }
161                secondTen.style.top = (- cSecond.substr(0, 1) * numHeight) + 'vw';
162                secondOne.style.top = (- cSecond.substr(1, 1) * numHeight) + 'vw';
163
164                setTimeout(countdown, 10);
165
166            } else {
167            }
168        }
169      countdown();
170      }
171    });
172  });
173

html
1<div id="countdown-unit">
2  <div><img src="images/number.png" id="day-ten" alt=""></div>
3  <div><img src="images/number.png" id="day-one" alt=""></div>
4  <div><img src="images/time.png" alt=""></div>
5  <div><img src="images/number.png" id="hour-ten" alt=""></div>
6  <div><img src="images/number.png" id="hour-one" alt=""></div>
7  <div><img src="images/time.png" alt=""></div>
8  <div><img src="images/number.png" id="minute-ten" alt=""></div>
9  <div><img src="images/number.png" id="minute-one" alt=""></div>
10  <div><img src="images/time.png" alt=""></div>
11  <div><img src="images/number.png" id="second-ten" alt=""></div>
12  <div><img src="images/number.png" id="second-one" alt=""></div>
13</div>