Sinatra/Ruby:

get '/getstats' do
                `sh /var/www/netspeed.sh wlan4`
                "test"
end

HTML:

var xmlhttp2=new XMLHttpRequest();
                 xmlhttp2.open("GET","http://"+new_ip+":/getstats",true);
                 xmlhttp2.setRequestHeader('Authorization', 'Basic 4=');
                 xmlhttp2.send();
                 xmlhttp2.onreadystatechange = function() {
                 if (xmlhttp2.readyState == 4 ) {
                 bandwidth_var.value = xmlhttp2.responseText;
                                                }
                                                          }