hello any help with the chatbox

[jackel1212]

hello guys i have custom chat box and i have something i want to change it to other button 


this my chat box 




i want change it to this button 






this code button anyone help me change it to make like up image

<div style="width: 100%; margin: 0 auto; text-align: center">
								<form name="mychatbox_post_form" method="POST" id="mychatbox_post_form">
									<input type="text" id="mychatbox_message" name="message" class="textbox" style="width: 200px" /> <input type="submit" value="{$lang->mychatbox_post}" id="mychatbox_post" class="button" name="submit" /> <div id="mychatbox_spinner" style="display: none"><img src="{$theme['imgdir']}/spinner.gif" /></div>