Submit button floated to the right jumps back to the left for the moment of submission

I have styled submit button with an image and floated it right:

#comment-form #edit-submit, input#ajax-comments-submit {
background: transparent url(../images/post.png) no-repeat;
text-indent: -999em;
width: 60px;
height: 29px;
float:right;
margin-bottom: 20px;
}

Everything looks fine, however when I click on submit image button it is floated back to the left for the short duration of submit process. Nevertheless which lasts just a short moment, would be very nice to have submit button on the side all the time.