Unable to disable button in magento

Question

 <form action="<?php echo Mage::getUrl('abc_checkout/cart/placeorder'); ?>" method="post" id="confirm_order_form" class="info-static" onsubmit="return submitOrder();">
.
.
.
.

    <div class="buttons-set">
    <p class="back-link"><span onclick="history.go(-1);
                    return true;" class="engine-btn">Back</span></a></p>
    <button type="submit" title="<?php echo $this->__('Place your order') ?>" class="engine-btn continue"><span><span><?php echo $this->__('Place your order') ?></span></span></button>
    <div class="mt30">
        <?php echo $this->__('Please be patient.'); ?>
    </div>
</div>
</form>

I want to disable this submit button after one click on front end.

Answer 1

use jquery for disable button

$(function(){
 $(".engine-btn").click(function () {
   $(".engine-btn").attr("disabled", true);
   $('#yourFormId').submit();
 });
});

Answer 2

on the <button> tag add "onclick"="jQuery(this).disabled = true;"

Answer 3

jQuery now has the .one() function that limits any given event (such as "submit") to one occurrence.

For Example:

$('#myForm').one('submit', function() {
    $(this).find('input[type="submit"]').attr('disabled','disabled');
});

I hope this will help you.