In the add method of the common.js file it sends an ajax request to the controller product\/compare with the product id \u00a0 and calls the add method of the controller.<\/p>\n
var compare = {\r\n\u00a0\u00a0 \u00a0'add': function(product_id) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0$.ajax({\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0url: 'index.php?route=product\/compare\/add',\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0type: 'post',\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0data: 'product_id=' + product_id,\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0dataType: 'json',\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0success: function(json) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0$('.alert').remove();\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0if (json['success']) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0$('#content').parent().before('<div class=\"alert alert-success\"><i class=\"fa fa-check-circle\"><\/i> ' + json['success'] + ' <button type=\"button\" class=\"close\" data-dismiss=\"alert\">×<\/button><\/div>');\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0$('#compare-total').html(json['total']);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0$('html, body').animate({ scrollTop: 0 }, 'slow');\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0},<\/pre>\nIn the controller it first check for the compare index in the sesson array exist or not. If not then it create an index of compare in session of array type. After that get the product inforamtion and check for product id valid.<\/p>\n
if (!isset($this->session->data['compare'])) {\r\n $this->session->data['compare'] = array();\r\n}\r\n<\/pre>\nAfter that it get the product information and and if the product find then it check that it is already added for compare or not and if it is not already in compare list then it checks already 4 products are added for compare then it remove the first product and kept only last 4 product for compare in that array.<\/p>\n
$product_info = $this->model_catalog_product->getProduct($product_id);\r\n\r\n\/\/Check If product exist \r\nif ($product_info) {\r\n \/\/Check that product is not already added for compare\r\n\tif (!in_array($this->request->post['product_id'], $this->session->data['compare'])) {\r\n \r\n \/\/If already 4 product in compare then it shift first product and kept only last 4 prodcut for compare\r\n\t if (count($this->session->data['compare']) >= 4) {\r\n\t\t array_shift($this->session->data['compare']);\r\n\t }\r\n\t $this->session->data['compare'][] = $this->request->post['product_id'];\r\n\t}\r\n\t$json['success'] = sprintf($this->language->get('text_success'), $this->url->link('product\/product', 'product_id=' . $this->request->post['product_id']), $product_info['name'], $this->url->link('product\/compare'));\r\n\t$json['total'] = sprintf($this->language->get('text_compare'), (isset($this->session->data['compare']) ? count($this->session->data['compare']) : 0));\r\n}\r\n<\/pre>\nWhen click on the comapre list after adding the products it iterate the compare index of the session and fetch the product inforamtion from their product id. It shows the name,image,price,special offer on product,description,model,manufacturer,availability,minimum (how many minimum product can buy),rating,reviews,weight,length,width,height and product attribute of the product during compare the product.<\/p>\n
![\"\"](\"https:\/\/cdnblog.webkul.com\/blog\/wp-content\/uploads\/2017\/02\/image1-1.png\")
<\/p>\n","protected":false},"excerpt":{"rendered":"