create plugins to detect suspicious ajax

Question

I want to make browser extension for Firefox that detect the ajax code of of website that load the hidden page and redirect to new page ,like if user visit index.php where ajax load the two pages one is hiddenpage.php and redirect to new.php . Is there any other solution to detect this ajax at client side.

if (xmlhttp.readyState==4 && xmlhttp.status==200)
                {
                    //document.getElementById("myDiv").innerHTML="";
                }
            }
            xmlhttp.open("GET","hidden.php",true);
            xmlhttp.send();
        }

HTML

<a href="new.php" onclick="function();">click here</a>

Answer 1

document.addEventListener('DOMContentLoaded', function() {
    getCurrentTabUrl(function(url) {
        fetchData(url);
    });
});

function fetchData(url)
{
    var xhr = new XMLHttpRequest();
    xhr.open("GET", url, true);
    xhr.onreadystatechange=function()
    {
        if (xhr.readyState==4 && xhr.status==200)
        {
            var data = xhr.responseText;
            var  index = data.indexOf('XMLHttpRequest');
            if(index != -1){
                document.getElementById("status").innerHTML = "The page contains AJAX requests";
            }else{
                document.getElementById("status").innerHTML = "Page doesn't contains AJAX";
            }
            //document.getElementById("status").innerHTML = data;
        }
    }
    //xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    //xhr.setRequestHeader("Access-Control-Allow-Origin", "*");
    //xhr.setRequestHeader("Access-Control-Request-Method", "POST");
    xhr.send();
}

function getCurrentTabUrl(callback) {
    var queryInfo = {
    active: true,
    currentWindow: true
    };
    chrome.tabs.query(queryInfo, function(tabs) {
        var tab = tabs[0];
        var url = tab.url;
        console.assert(typeof url == 'string', 'tab.url should be a string');
        callback(url);
    });
}
just go through this code you will get the better help