How to set the size of the new window? as well as its centering
<a href="javascript:open_window(''cart.php?addproduct={$product_info.productID}{counter name='select_counter_hidden' start=0 skip=1 print=false}{counter name='select_counter_hidden_extra' start=0 skip=1 print=false}{section name=i loop=$product_extra}{if $product_extra[i].option_type eq 1}{section name=s loop=$product_extra[i].option_show_times}&option_select_hidden_{counter name=select_counter_hidden}='+document.HiddenFieldsForm.option_select_hidden_{counter name=select_counter_hidden_extra}.value+'{/section}{/if}{/section}&count='+document.MainForm.totalcount.value+'',400,300);" ')">открыть</a>
400,300- Grundyopen_windowfunction isopen_windowand what parameters are passed to it after all? not a sample is not clear what, and the final line? Which browser did you check? - Grundywindow.open(). - Marat Tanalin