i modified the code, as giving it an actual emote :smackdown: freaks me out for some reason. im pretty sure i made it just put in an actual image tag
the entire code is now
document.getElementsByTagName("td")[17].innerHTML += '<a href="javascript:replaceText(\'[img height=50]http://swololol.com/sd[/img]\', document.forms.postmodify.message);"><img src="http://swololol.com/sd" width="35" height="30" align="bottom" alt="" title="" border="0"></a>';

no replacement text or modifying the post button, it's now just a button you click to make bbcode quickly (which could be used to make other useful things, like instant table maker or color maker or simply a place to store many emote-like images or even simple text)