JSFiddle - React, Tailwind, and code Playground
HTML
<form action="" method="post" onSubmit="if (this.message.value == '') {return false;}">
<textarea id="message" name="message" maxlength="35"></textarea>
<input id="send" type="image" src="http://dl.dropbox.com/u/26827941/submit.png" value="Submit">
</form>
JavaScript
$(function(){
$("#send").submit(function(e){
if($("#message").val()==""))
{
e.preventDefault();
}
});
});