There’s no way to preserve the leading 0 in JavaScript. However, you can consider this id as a string and pass as an argument.
Example
You can try to run the following code to preserve leading 0 by making it a string −
<html>
<head>
<script>
function sayHello(name, age, id) {
document.write (name + " is " + age + " years old, with id = "+id);
}
</script>
</head>
<body>
<p>Click the following button to call the function</p>
<form>
<input type="button" onclick="sayHello('John', 26, '0678')"
value="Display Employee Info">
</form>
</body>
</html>