how to set element before element in javascript code example

Example 1: javascript add div before element

var my_elem = document.getElementById('my_id');

var span = document.createElement('span');
    span.innerHTML = '*';
    span.className = 'asterisk';

my_elem.parentNode.insertBefore(span, my_elem);

Example 2: javascript insert html before element

// add without creating a new element
document.getElementById('my_id')
.insertAdjacentHTML('beforebegin', 'your_html_code');