Question

Though I’ve programming experience, am completely new to GS, JS, or anything related to UI.

Scenario: Making an AJAX call from Greasemonkey script to a Servlet

Greasemonkey/JS Code:

function getResultsData(query){
alert("Getting the Data");
$.ajax( 
    {
    cache: false,   
    data: {"q":query},      
    dataType:"text",
    url: "http://myserver.com:8000/search?",
    success: processData        
    }); //end of $.ajax }

function processData(data){
alert("Got the data");
var myResultDiv = document.getElementById("searchRes");
myResultDiv.innerHTML = data; }

Servlet Code:

        System.out.println("-----------This is an AJAX call------------------");
        //Commented the original logic
        resp.setContentType("text/plain");
        resp.setCharacterEncoding("UTF-8");
        resp.getWriter().write("Text from Servlet");

Problem:

• GS/JS code works perfectly if the url (in $.ajax) is some other existing API. Response reflects in the UI

• However, when I give my server’s url, I can observe in the Firebug.Console that there’s no http response for that call but the status says 200 OK with the whole entry turned ‘RED’.

• When I test the url copied from Firebug’s ‘http call entry’, it’s working perfectly as I can see the response ‘Text from Servlet’ on the new tab.

Can someone please help.

NOTE Website on which greasemonkey runs, and my server belong to same domain, i.e.

Greasemonkey website: wwww.example.com

My server: http://www.myserver.example.com

Answer 1

Thanks to @mattedgod. His comment triggered me to research more and I found the answer.

Add the following snippet to make it work.

response.setHeader("Access-Control-Allow-Origin", "*");

Surprisingly, it doesn’t work if I explicitly specify my own server’s full http address in the header. I yet to find out why.