javascriptでdocumentを使うと改行されるのを防ぐ方法を教えて下さい。

javascriptで改行されてしまいます。

こちらのコードで試してもらったら分かると思うのですが、電卓を作っていまして、
「ー」を押して引き算を計算すると答えと上の計算式が改行されて被ってしまいます。
どうしたらいいのかを教えて下さい。

javascript
1<title>電卓</title>
2<link rel="icon" href="https://raw.githubusercontent.com/sugoruru/rurukun3-save/main/favicon.ico" id="favicon">
3<link rel="apple-touch-icon" sizes="180x180" href="https://raw.githubusercontent.com/sugoruru/rurukun3-save/main/apple-touch-icon-180x180.png">
4<style>
5body {
6width: 95%;
7height: 95%;
8background: linear-gradient(#84C1FF, #A8B3FF);
9padding: 0;
10}
11.box1 {
12  width: 415px;
13  height: 80px;
14  position:absolute;
15  top:13px;
16  left:500px;
17  background: #0091EA;
18  border: solid;
19}
20.box2 {
21  width: 415px;
22  height: 10px;
23  position:absolute;
24  top:0px;
25  left:500px;
26  background: #000000;
27  border: solid;
28}
29.box3 {
30  width: 100px;
31  height: 90px;
32  position:absolute;
33  top:96px;
34  left:500px;
35  background: #3cb371;
36  border: solid;
37}
38.box5 {
39  width: 100px;
40  height: 90px;
41  position:absolute;
42  top:96px;
43  left:605px;
44  background: #3cb371;
45  border: solid;
46}
47.box6 {
48  width: 100px;
49  height: 90px;
50  position:absolute;
51  top:96px;
52  left:710px;
53  background: #3cb371;
54  border: solid;
55}
56.box7 {
57  width: 100px;
58  height: 90px;
59  position:absolute;
60  top:96px;
61  left:815px;
62  background: #3cb371;
63  border: solid;
64}
65.box8 {
66  width: 100px;
67  height: 90px;
68  position:absolute;
69  top:190px;
70  left:500px;
71  background: #3cb371;
72  border: solid;
73}
74.box9 {
75  width: 100px;
76  height: 90px;
77  position:absolute;
78  top:190px;
79  left:605px;
80  background: #3cb371;
81  border: solid;
82}
83.box10 {
84  width: 100px;
85  height: 90px;
86  position:absolute;
87  top:190px;
88  left:710px;
89  background: #3cb371;
90  border: solid;
91}
92.box12 {
93  width: 100px;
94  height: 90px;
95  position:absolute;
96  top:190px;
97  left:815px;
98  background: #3cb371;
99  border: solid;
100}
101.box14 {
102  width: 100px;
103  height: 90px;
104  position:absolute;
105  top:284px;
106  left:500px;
107  background: #3cb371;
108  border: solid;
109}
110.box15 {
111  width: 100px;
112  height: 90px;
113  position:absolute;
114  top:284px;
115  left:605px;
116  background: #3cb371;
117  border: solid;
118}
119.box16 {
120  width: 100px;
121  height: 90px;
122  position:absolute;
123  top:284px;
124  left:710px;
125  background: #3cb371;
126  border: solid;
127}
128.box17 {
129  width: 100px;
130  height: 90px;
131  position:absolute;
132  top:284px;
133  left:815px;
134  background: #3cb371;
135  border: solid;
136}
137.box18 {
138  width: 100px;
139  height: 90px;
140  position:absolute;
141  top:378px;
142  left:500px;
143  background: #3cb371;
144  border: solid;
145}
146.box19 {
147  width: 100px;
148  height: 90px;
149  position:absolute;
150  top:378px;
151  left:605px;
152  background: #3cb371;
153  border: solid;
154}
155.box20 {
156  width: 100px;
157  height: 90px;
158  position:absolute;
159  top:378px;
160  left:710px;
161  background: #3cb371;
162  border: solid;
163}
164.box21 {
165  width: 100px;
166  height: 90px;
167  position:absolute;
168  top:378px;
169  left:815px;
170  background: #3cb371;
171  border: solid;
172}
173.box22 {
174  width: 100px;
175  height: 90px;
176  position:absolute;
177  top:472px;
178  left:500px;
179  background: #3cb371;
180  border: solid;
181}
182.box24 {
183  width: 100px;
184  height: 90px;
185  position:absolute;
186  top:472px;
187  left:605px;
188  background: #3cb371;
189  border: solid;
190}
191.box25 {
192  width: 100px;
193  height: 90px;
194  position:absolute;
195  top:472px;
196  left:710px;
197  background: #3cb371;
198  border: solid;
199}
200.box26 {
201  width: 100px;
202  height: 90px;
203  position:absolute;
204  top:472px;
205  left:815px;
206  background: #3cb371;
207  border: solid;
208}
209.box11 {
210font-size:70px;
211position:absolute;
212top:-10px;
213left:8px;
214}
215.box4 {
216font-size:70px;
217position:absolute;
218top:-10px;
219left:30px;
220}
221.box30 {
222font-size:70px;
223position:absolute;
224top:-10px;
225left:10px;
226}
227.box13 {
228font-size:70px;
229position:absolute;
230top:-10px;
231left:16px;
232}
233.box23 {
234font-size:40px;
235position:absolute;
236top:15px;
237left:7px;
238}
239.box28 {
240font-size:37px;
241position:absolute;
242top:10px;
243}
244.box27 {
245position:absolute;
246top:80px;
247}
248.box29 {
249font-size:20px;
250position:absolute;
251left:510px;
252top:15px;
253}
254</style>
255<div class="box27">
256<div class="box1"><div class="box28"><div id="a"></div></div></div>
257<div class="box29"><div id="b"></div></div>
258<div class="box2"></div>
259<div class="box3" onclick="_7()"><div class="box4">7</div></div>
260<div class="box5" onclick="_8()"><div class="box4">8</div></div>
261<div class="box6" onclick="_9()"><div class="box4">9</div></div>
262<div class="box7" onclick="_AC()"><div class="box11">AC</div></div>
263<div class="box8" onclick="_4()"><div class="box4">4</div></div>
264<div class="box9" onclick="_5()"><div class="box4">5</div></div>
265<div class="box10" onclick="_6()"><div class="box4">6</div></div>
266<div class="box12" onclick="_e()"><div class="box13">÷</div></div>
267<div class="box14" onclick="_1()"><div class="box4">1</div></div>
268<div class="box15" onclick="_2()"><div class="box4">2</div></div>
269<div class="box16" onclick="_3()"><div class="box4">3</div></div>
270<div class="box17" onclick="_d()"><div class="box13">×</div></div>
271<div class="box18" onclick="_a()"><div class="box4">.</div></div>
272<div class="box19" onclick="_0()"><div class="box4">0</div></div>
273<div class="box20" onclick="_g()"><div class="box4">=</div></div>
274<div class="box21" onclick="_c()"><div class="box13">ー</div></div>
275<div class="box22" onclick="_00()"><div class="box30">00</div></div>
276<div class="box24" onclick="_f()"><div class="box13">％</div></div>
277<div class="box25" onclick="_C()"><div class="box4">C</div></div>
278<div class="box26" onclick="_b()"><div class="box13">＋</div></div></div>
279<script>
280var date1 = "0";
281var date2 = "";
282var date3 = "0";
283var anser = "";
284var operator = "";
285var ok = 0;
286function _9() {
287if(date2 == ""){
288if(date1.length <= 9){
289date1 = date1 + "9"
290}
291}else{
292if(date3.length <= 9){
293date3 = date3 + "9"
294}
295}
296}
297function _8() {
298if(date2 == ""){
299if(date1.length <= 9){
300date1 = date1 + "8"
301}
302}else{
303if(date3.length <= 9){
304date3 = date3 + "8"
305}
306}
307}
308function _7() {
309if(date2 == ""){
310if(date1.length <= 9){
311date1 = date1 + "7"
312}
313}else{
314if(date3.length <= 9){
315date3 = date3 + "7"
316}
317}
318}
319function _00() {
320if(date2 == ""){
321if(date1.length <= 8){
322date1 = date1 + "00"
323}
324}else{
325if(date3.length <= 9){
326date3 = date3 + "00"
327}
328}
329}
330function _6() {
331if(date2 == ""){
332if(date1.length <= 9){
333date1 = date1 + "6"
334}
335}else{
336if(date3.length <= 9){
337date3 = date3 + "6"
338}
339}
340}
341function _5() {
342if(date2 == ""){
343if(date1.length <= 9){
344date1 = date1 + "5"
345}
346}else{
347if(date3.length <= 9){
348date3 = date3 + "5"
349}
350}
351}
352function _4() {
353if(date2 == ""){
354if(date1.length <= 9){
355date1 = date1 + "4"
356}
357}else{
358if(date3.length <= 9){
359date3 = date3 + "4"
360}
361}
362}
363function _3() {
364if(date2 == ""){
365if(date1.length <= 9){
366date1 = date1 + "3"
367}
368}else{
369if(date3.length <= 9){
370date3 = date3 + "3"
371}
372}
373}
374function _2() {
375if(date2 == ""){
376if(date1.length <= 9){
377date1 = date1 + "2"
378}
379}else{
380if(date3.length <= 9){
381date3 = date3 + "2"
382}
383}
384}
385function _1() {
386if(date2 == ""){
387if(date1.length <= 9){
388date1 = date1 + "1"
389}
390}else{
391if(date3.length <= 9){
392date3 = date3 + "1"
393}
394}
395}
396function _0() {
397if(date2 == ""){
398if(date1.length <= 9 &&(date1.substr(date1.lenget-1,date1.lenget) !== "0")){
399date1 = date1 + "0"
400}
401}else{
402if(date3.length <= 9){
403date3 = date3 + "0"
404}
405}
406}
407function _a() {
408if(date2 == ""){
409if(date1.length <= 8 && date1 !== "" && (!(date1.match(/[.]/)))){
410date1 = date1 + "."
411}
412}else{
413if(date3.length <= 9){
414date3 = date3 + "."
415}
416}
417}
418function _AC() {
419date1 = "0";
420date2 = "";
421date3 = "0";
422anser = "";
423ok = 0;
424document.getElementById('b').innerHTML = "";
425}
426function _b() {
427date2 = 1;
428}
429function _c() {
430date2 = 2;
431ok = 0;
432}
433function _d() {
434date2 = 3;
435}
436function _e() {
437date2 = 4;
438}
439function _f() {
440date2 = 5;
441}
442function _C() {
443date3 = "0";
444}
445function _g() {
446if(date2 == 1){
447anser = Number(date1) + Number(date3);
448ok = 1;
449}
450if(date2 == 2){
451anser = Number(date1) - Number(date3);
452ok = 1;
453}
454if(date2 == 3){
455anser = Number(date1) * Number(date3);
456ok = 1;
457}
458if(date2 == 4){
459anser = Number(date1) / Number(date3);
460ok = 1;
461}
462if(date2 == 5){
463anser = Number(date1) % Number(date3);
464ok = 1;
465}
466}
467function main() {
468if(date2 == ""){
469document.getElementById('a').innerHTML = date1;
470}else{
471if(ok == 0){
472document.getElementById('a').innerHTML = date3;
473document.getElementById('b').innerHTML = date1 + operator;
474}else{
475document.getElementById('b').innerHTML = date1 + operator + date3;
476document.getElementById('a').innerHTML = anser;
477}
478}
479if(date1.substr(0,1) == 0 && !(date1.substr(1,1) == "." || date1.substr(1,1) == "")){
480date1 = date1.substr(1,date1.length);
481}
482if(date3.substr(0,1) == 0 && !(date3.substr(1,1) == "." || date3.substr(1,1) == "")){
483date3 = date3.substr(1,date3.length);
484}
485if(date2 == 1){
486operator = "+"
487}
488if(date2 == 2){
489operator = "-"
490}
491if(date2 == 3){
492operator = "*"
493}
494if(date2 == 4){
495operator = "/"
496}
497if(date2 == 5){
498operator = "%"
499}
500requestAnimationFrame(main);
501}
502requestAnimationFrame(main);
503</script>