Flask Jinja2 Page Freezes after sometime - ajax

Question

I've deployed a simple Flask Application on Apache2 in Ubuntu 16.04 x64(Alibaba Cloud) with mod_wsgi. I'm using mysql as my database server on the same ubuntu server instance. The python version is 3.5.
In the backend of the application I'm processing data from some database queries from some relatively large database tables.
In frontend page, I'm visualizing the data I'm expecting to get from the backend by D3PLUS JS library. And, in a single page, I'm showing 4 charts/graphs in 4 html divs and two other divs to show text data. All of the requests for the data is currently handled by ajax post.
I've ensured CSRF protection for ajax request by
var csrf_token = "{{ csrf_token() }}";
$.ajaxSetup({
beforeSend: function(xhr, settings) {
if (!/^(GET|HEAD|OPTIONS|TRACE)$/i.test(settings.type) && !this.crossDomain) {
xhr.setRequestHeader("X-CSRFToken", csrf_token);
}
}
});
The post request requires around 20-25 seconds to get response normally from the backend. Here is the example of the post request:
$('#company_button').on('click', function(event) {
var company_name = ($('#company_select').select2('data'))[0].text;
if (company_name==null){
alert('Enter a name please!');
}
else{
handle_all(company_name);
}
event.preventDefault();
});
function handle_all(company_name){
show_loader();
//baike_getter(event,company_name);
//recommend_getter(company_name);
$.ajax({
type:"POST",
contentType: "application/json; charset=utf-8",
data : JSON.stringify({company_name : company_name}),
dataType: "json",
url: flask_util.url_for('_company_info_all'),
success: function (data) {
JSON.parse(data[0].recommendation);
remove_loader();
update_company(data[0].company_general[0]);
all_graphs(data[0].country,data[0].product,data[0].haiguan,data[0].shipping);
recommend_getter2(company_name);
baike_getter2(event,company_name);
}
});
}
The size of the JSON data got as response is around 5-10 KB and it includes Chinese text(Unicode).
The problem is that after two-three times of sending the batch(Actually only one request which handles processing everything in backend) of post request to backend, when data comes as response, the page freezes forever.
Any help will be encouraged. Thanks in advance !
Edit/Update: The charts/graphs I'm generating in this page are tree_map,pie,2 bar charts. All are with .format({"locale":"zh_CN"}). Version used D3Plus V1