Hi! I'm working on this prank for my friends. I'm not an experienced programmer, and although i want to become one one day, I only have limited time to do this prank on my friends. So here's the deal. I use a webpage https://www.webpage.com/lol/data.asp (will be replaced with URL in code since this forum has limits on new users). On this site there is a div called "data_div" and I want to inject some code so when the page loads (when i load the extension ofc), the data in the div is replaced by the data in my HTML document. In this document i only have a table with new data that will replace the original table. How would i do this?

So far by reading forum posts and using google to help me, I've made little progress since i'm new to programming.

This is the code I got.

Manifest.json

Code:
{  "name": "prank",
  "version": "0.1",
  "permissions": [
    "URL"
  ],
  "content_scripts": [
    {
      "matches": ["JQUERY URL", "URL"],
      "js": ["jquery-1.9.1.min.js", "myscript.js"],
      "run_at": "document_end"
    }
  ],
  "manifest_version": 2
}
myscript.js
Code:
chrome.extension.sendRequest({cmd: "read_file"}, function(html){
    $("data_div").html(html);
});
background.html
Code:
chrome.extension.onRequest.addListener(function(request, sender, sendResponse) {
    if(request.cmd == "read_file") {
        $.ajax({
            url: chrome.extension.getURL("cont.html"),
            dataType: "html",
            success: sendResponse
        });
    }
})
and the HTML table content in cont.html.

This doesn't work, and if someone could make this work, or write me a thing that works I'd be most grateful.

The extension loads but doesnt do anything when i go on the site. I'm not even sure if I can access the div on the site and change it or if this is the right way to do it. I'm all ears guys, please, please help me! I'd be willing to donate some bitcoins or money via paypal if someone gets this workin!