在每个Ajax调用上重新加载调用页面

Question

I need a page called via ajax to fully reload everytime I request it. Currently, when requested for the first time it loads the page correctly, but when requested the second time it loads with the previous result and then after 2 or 3 second loads the new result.

I want it to show a loading image while it reloads the page into my div.

See code I'm using below:

$io('#load_order_preview').on('click', function(){

            var portfolioName       = $io("#portfolioName").val();
            var instrumentType      = $io("#instrumentType").val();
            var securityName        = $io("#securityName").val();
            var orderType           = $io("#orderType").val();
            var priceType           = $io("#priceType").val();
            var quantityRequested   = $io("#quantityRequested").val();
            var orderTermName       = $io("#orderTermName").val();
            var limitPrice          = $io("#limitPrice").val();
            var stockPrice          = $io("#stockPrice").val();
            var stopPrice           = $io("#stopPrice").val();

            var dataString = 'portfolioName='+ portfolioName + '&instrumentType=' + instrumentType + '&securityName=' + securityName + '&orderType=' + orderType + '&priceType=' + priceType + '&quantityRequested=' + quantityRequested + '&orderTermName=' + orderTermName + '&limitPrice=' + limitPrice + '&stopPrice=' + stopPrice;

             $io('#load_popup_modal_orderpreview').load(
                 'load-preview.php?' + dataString
             }).modal({
             backdrop: 'static',
             keyboard: false
             }).show();

        });

I'd really like some help to solve this problem.

Thanks in advance.