a.js_submit {
  background: url("button-left.png") no-repeat scroll left center transparent;
  display: block;
  margin: 0 auto;
  text-align: center;
  text-decoration: none;
  width: 10em;
}

a.js_submit span {
  background: url("button-right.png") no-repeat scroll right center transparent;
  display: block;
  padding: 1.2em 2em;
}