"Add to cart" button doesn't work because of ReferenceError

"Add to cart" button doesn't work because of ReferenceError

I have an "Add to cart" button in my Magento theme, I haven't edited it
but it stopped working. It defenitely worked some time ago and
unfortunately I didn't catch the moment when things went wrong. When I'm
pressing the button nothing happens in frontend and I see the error
"Uncaught ReferenceError: productAddToCartForm is not defined" in console.
Here is the button HTML:
<button class="button btn-cart" title="Äîáàâèòü â êîðçèíó" type="button"
onClick="productAddToCartForm.submit(this)"><i
class="icon-basket"></i>Äîáàâèòü â êîðçèíó</button>
However, when I look at page source, the script is in the page:
<script type="text/javascript">
//<![CDATA[
var productAddToCartForm = new VarienForm('product_addtocart_form');
<?php if(Mage::getStoreConfig('buyshopconfig/options/ajax_add_to_cart')){?>
productAddToCartForm.submit = function(button, url) {
if (this.validator.validate()) {
var form = this.form;
var oldUrl = form.action;
if (url) {
form.action = url;
}
var e = null;
// Start of our new ajax code
if (!url) {
url = jQuery('#product_addtocart_form').attr('action');
}
url = url.replace("checkout/cart","ajax/index"); // New Code
var data = jQuery('#product_addtocart_form').serialize();
data += '&isAjax=1';
jQuery('#preloader .loader').fadeIn(300);
try {
jQuery.ajax( {
url : url,
dataType : 'json',
type : 'post',
data : data,
success : function(data) {
jQuery('#ajax_loader').hide();
if(data.status == 'ERROR'){
alert(data.message);
}else{
jQuery('#preloader .loader').hide();
if(jQuery('.ul_wrapper.toplinks')){
jQuery('.shoppingcart').replaceWith(data.sidebar);
}
jQuery(".shoppingcart .fadelink").bind({
mouseenter: function(e) {
jQuery(this).find(".shopping_cart_mini").stop(true,
true).fadeIn(300, "linear");
},
mouseleave: function(e) {
jQuery(this).find(".shopping_cart_mini").stop(true,
true).fadeOut(300, "linear");
}
});
if(jQuery('#topline .links')){
jQuery('#topline
.links').replaceWith(data.toplink);
}
jQuery('#preloader .inside').html('Òîâàð
"'data.name+'" áûë äîáàâëåí â âàøó êîðçèíó');
jQuery('#preloader .message').fadeIn(300);
setTimeout(function(){
jQuery('#preloader .message').fadeOut();
},1500)
}
}
});
} catch (e) {
}
// End of our new ajax code
this.form.action = oldUrl;
if (e) {
throw e;
}
}
}.bind(productAddToCartForm);
<?php }else { ?>
productAddToCartForm.submit = function(button, url) {
if (this.validator.validate()) {
var form = this.form;
var oldUrl = form.action;
if (url) {
form.action = url;
}
var e = null;
try {
this.form.submit();
} catch (e) {
}
this.form.action = oldUrl;
if (e) {
throw e;
}
if (button && button != 'undefined') {
button.disabled = true;
}
}
}.bind(productAddToCartForm);
<?php } ?>
productAddToCartForm.submitLight = function(button, url){
if(this.validator) {
var nv = Validation.methods;
delete Validation.methods['required-entry'];
delete Validation.methods['validate-one-required'];
delete Validation.methods['validate-one-required-by-name'];
// Remove custom datetime validators
for (var methodName in Validation.methods) {
if (methodName.match(/^validate-datetime-.*/i)) {
delete Validation.methods[methodName];
}
}
if (this.validator.validate()) {
if (url) {
this.form.action = url;
}
this.form.submit();
}
Object.extend(Validation.methods, nv);
}
}.bind(productAddToCartForm);
<?php if(!Mage::helper('lightboxes')->isActive()):?>
jQuery("a.video").click(function() {
jQuery.fancybox({
'padding' : 0,
'autoScale' : false,
'transitionIn' : 'none',
'transitionOut' : 'none',
'title' : this.title,
'width' : 680,
'height' : 495,
'href' : this.href.replace(new RegExp("watch\\?v=", "i"),
'v/'),
'type' : 'swf',
'swf' : {
'wmode' : 'transparent',
'allowfullscreen' : 'true'
}
});
return false;
});
<?php endif;?>
//]]>
Could anyone give the answer what is the problem with this function?
You can reproduce the error on
http://koketka-online.ru/index.php/women/sumka-jimmi-choo-belaya.html
page.