How to place two Javascript functions inside one script source file?

I am absolutely new to Javascript. And I am making a web project that changes the styles of two div elements using select/option values. However, it will not work when I attempt to put the codes together.

This is the code:

<html>
<head>

<style>
div{
  width:100px;
  height:50px;
  border:1px solid Black;
  margin: 10px; padding:6px;}

select{
  width:150px;
  height:30px;}
</style>
</head>
<body>
<div class="Box1" id="Box1"> This is the First Box. </div>
<div class="Box2" id="Box2"> This is the Second Box. </div>

<br><br>

<h4>First Box Style</h4>
<select name="font" id="1stfont">
<option value="Arial">Arial</option>
<option value="Tahoma">Tahoma</option>
<option value="Georgia">Georgia</option>
</select>

<select name="foreground" id="1stforeground">
<option value="Black">Black</option>
<option value="White">White</option>
<option value="Brown">Brown</option>
</select>

<select name="background" id="1stbackground">
<option value="White">White</option>
<option value="Tan">Tan</option>
<option value="Black">Black</option>
</select>

<select name="bgImage" id="1stbgImage">
<option value="url('https://sadhost.neocities.org/images/tiles/leavesbg.gif')">Pattern #1</option>
<option value="url('https://sadhost.neocities.org/images/tiles/tumblr_inline_mlkxsmQayT1r53miq540.gif')">Pattern #2</option>
<option value="url('https://sadhost.neocities.org/images/tiles/gifbground-804-0005.gif')">Pattern #3</option>
</select> 

<br><br>

<h4>Second Box Style</h4>
<select name="font" id="2ndfont">
<option value="Arial">Arial</option>
<option value="Tahoma">Tahoma</option>
<option value="Georgia">Georgia</option>
</select>

<select name="foreground" id="2ndforeground">
<option value="Black">Black</option>
<option value="White">White</option>
<option value="Brown">Brown</option>
</select>

<select name="background" id="2ndbackground">
<option value="White">White</option>
<option value="Tan">Tan</option>
<option value="Black">Black</option>
</select>

<select name="bgImage" id="2ndbgImage">
<option value="url('https://sadhost.neocities.org/images/tiles/leavesbg.gif')">Pattern #1</option>
<option value="url('https://sadhost.neocities.org/images/tiles/tumblr_inline_mlkxsmQayT1r53miq540.gif')">Pattern #2</option>
<option value="url('https://sadhost.neocities.org/images/tiles/gifbground-804-0005.gif')">Pattern #3</option>
</select> 

<script>
var change = document.getElementById('Box1');

document.getElementById('1stforeground').addEventListener('change', function(){
  change.style.color = this.value;
});

document.getElementById('1stfont').addEventListener('change', function(){
  change.style.fontFamily = this.value;
});

document.getElementById('1stbackground').addEventListener('change', function(){
  change.style.backgroundColor = this.value;
});

document.getElementById('1stbgImage').addEventListener('change', function(){
 change.style.backgroundImage = this.value;
});

var change = document.getElementById('Box2');

document.getElementById('2ndforeground').addEventListener('change', function(){
  change.style.color = this.value;
});

document.getElementById('2ndfont').addEventListener('change', function(){
  change.style.fontFamily = this.value;
});

document.getElementById('2ndbackground').addEventListener('change', function(){
  change.style.backgroundColor = this.value;
});

document.getElementById('2ndbgImage').addEventListener('change', function(){
 change.style.backgroundImage = this.value;
});

</script>
</body>
</html>

I already tried the following and I probably did all of them wrong:

  1. Link to two source files.
  2. Combine them into one script (whether with function() or combining variables)
  3. Place them as separate scripts inside an html document.

EDIT: It only changes the second box.

EDIT: I am using it to make a web button maker on my secondary domain webhost website.