previousSibling

js/script.js

function funMake() {
var val0 = document.getElementById('d1');
val0.innerHTML = '<h3>' + document.getElementById('p1').previousSibling.innerHTML + '</h3>';
var val1 = document.getElementById('d2');
val1.innerHTML = '<h3>' + document.getElementById('p2').previousSibling.innerHTML + '</h3>';
}

function funMake() {
var val0 = document.getElementById('d1');
val0.innerHTML = '<h3>' + document.getElementById('p1').previousSibling.innerHTML + '</h3>';
var val1 = document.getElementById('d2');
val1.innerHTML = '<h3>' + document.getElementById('p2').previousSibling.innerHTML + '</h3>';
}

index.html

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>New Page</title>
<script src="js/script.js"></script>
</head>
<body>
<div>
<p>Hello World!</p>
<p id="p1">Привет Мир!</p>
<p>To be or not to be?</p>
</div>
<div id="d1"></div>
<div>
<p>Hello World!</p><p id="p2">Привет Мир!</p><p>To be or not to be?</p>
</div>
<div id="d2"></div>
<script>
funMake();
</script>
</body>
</html>

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>New Page</title>
<script src="js/script.js"></script>
</head>
<body>
<div>
<p>Hello World!</p>
<p id="p1">Привет Мир!</p>
<p>To be or not to be?</p>
</div>
<div id="d1"></div>
<div>
<p>Hello World!</p><p id="p2">Привет Мир!</p><p>To be or not to be?</p>
</div>
<div id="d2"></div>
<script>
funMake();
</script>
</body>
</html>