<!DOCTYPE html> <html> <head> <script> function boom() { var c = document.getElementById("c"); var space = document.createTextNode(" "); c.parentNode.insertBefore(space, c); } </script> </head> <body style="font-family: monospace;" onload="boom();"> <div style="width: 3ch; border: 1px solid orange;"> <span>a</span> <span>b</span><span id="c">c</span> </div> </body> </html>