Stopping content script in chrome extension

Question

I have developed chrome extension , I have added ,

 chrome.browserAction.onClicked.addListener

which will start the script once clicked on , the script in turn will add a div at the bottom of the web page on the tab the browser action is clicked ,

All I have to do is , I need to add a close link which will stop the content script and close the div at the bottom ,

I have tried windows.close() , self.close() but nothing seems to work ,I would atleast want it to work in a way that 2nd time some one clicks on browser action, the script should stop.

Here is my code,

background.js

 chrome.browserAction.onClicked.addListener( function() {
 chrome.tabs.executeScript( { file: 'myscript.js' } );
 });

myscript.js

document.body.appendChild(div);
   document.addEventListener("click", 
 function (e) {
 e.preventDefault();
var check = e.target.getAttribute("id");
var check_class = e.target.getAttribute("class");
   if(check=="ospy_" || check=="ospy_id" || check=="ospy_text" || check=="ospy_el" ||   check=="ospy_class" || check=="ospy_name" || check=="ospy_href" || check=="ospy_src"|| check=="ospy_wrapper"|| check=="ospy_style"|| check=="ospy_rx"|| check=="ospy_con"|| check_class=="ospy_td"|| check=="ospy_main_tab"|| check_class=="ospy_tab" || check_class=="ospy_ip"|| check_class=="ospy_lab")
   {

       }
 else{
   document.getElementById('ospy_id').value = "";
   document.getElementById('ospy_class').value = "";
   document.getElementById('ospy_el').value = "";
   document.getElementById('ospy_name').value = "";
   document.getElementById('ospy_style').value = "";
   document.getElementById('ospy_href').value = "";
   document.getElementById('ospy_text').value = "";
   document.getElementById('ospy_src').value = "";
   document.getElementById('ospy_con').value = "";
   document.getElementById('ospy_').value = "";
   document.getElementById('ospy_rx').value = "";


  var dom_id=e.target.getAttribute("id");
 // var dom_id = e.target.id.toString();
  var dom_name = e.target.name.toString();
  var dom_class = e.target.className.toString();
 // var dom_class = this.class;
  var dom_html = e.target.innerHTML;
  var dom_href = e.target.getAttribute("href");
  var dom_text = e.target.text;
  var dom_el= e.target.tagName;
  var dom_src= e.target.src;
  //var XPATH = e.target.innerHTML;
  var rel_xpath = "";
  var field ="";
  var field_value = "";

  field="id";
  field_value = dom_id;
  rel_xpath = dom_el+"[@"+field+"='"+field_value+"']";
  if(dom_id == null){
      field="href";
     field_value= dom_href;
     //var rel_xpath = dom_el+"[contains(text(), '"+dom_text+"')]";
    rel_xpath = dom_el+"[@"+field+"='"+field_value+"']";
      if(dom_href==null || dom_href=="#")
          {
           field="src";
          field_value= dom_src;
           rel_xpath = dom_el+"[@"+field+"='"+field_value+"']";
          //rel_xpath = "nope nothing";
          if(dom_src==null)
          {
            var rel_xpath = dom_el+"[contains(text(), '"+dom_text+"')]";
            if(dom_text=="")
          {
            field="class";
          field_value= dom_class;
           rel_xpath = dom_el+"[@"+field+"='"+field_value+"']";

              }
              }

          }

      }

  var con_xpath = "";
  var con_xpath = dom_el+"[contains(text(), '"+dom_text+"')]";
            if(dom_text==null)
          {
            con_xpath = "NA";

              }
var css ="color: ";
css += getComputedStyle(e.target).color;
css +="\nWidth: ";
css += getComputedStyle(e.target).width;
css +="\nHeight: ";
css += getComputedStyle(e.target).height;
css +="\nbg: ";
css += getComputedStyle(e.target).background;
css +="\nfont: ";
css += getComputedStyle(e.target).font;
css +="\nvertical-align: ";
css += getComputedStyle(e.target).verticalalign;
css +="\nmargin: ";
css += getComputedStyle(e.target).margin;
var node = getXPath(e.target.parentNode);



   document.getElementById('ospy_id').value = dom_id;
   document.getElementById('ospy_class').value = dom_class;
   document.getElementById('ospy_el').value = dom_el;
   document.getElementById('ospy_name').value = dom_name;
   document.getElementById('ospy_style').value = css;
   document.getElementById('ospy_href').value = dom_href;
   document.getElementById('ospy_text').value = dom_text;
   document.getElementById('ospy_src').value = dom_src;
   document.getElementById('ospy_').value = node;
   document.getElementById('ospy_rx').value =rel_xpath;
   document.getElementById('ospy_con').value =con_xpath;

 }}, 
    false);

Answer 1

window.close() is for closing a window, so no wonder it does not work.

"Unloading" a content-script is not possible, but if you want to remove an element (e.g. your div) from the DOM, just do:

elem.parentNode.removeChild(elem);

_{(Whether you bind this behaviour to a link/button in your <div> or have the browser-action, trigger an event in the background-page that sends a message to the corresponding content-script which in turn removes the element is up to you. (But clearly the former is much more straight-forward and efficient.)}

---

If you, also, want your script to stop performing some other operation (e.g. handling click events) you could (among other things) set a flag variable to false (when removing the <div>) and then check that flag before proceeding with the operation (e.g. handling the event):

var enabled = true;
document.addEventListener('click', function (evt) {
    if (!enabled) {
        /* Do nothing */
        return;
    }

    /* I am 'enabled' - I'll handle this one */
    evt.preventDefault();
    ...

/* In order to "disable" the content-script: */
div.parentNode.removeChild(div);
enabled = false;

---

Notes:

• If you plan on re-enabling the content-script upon browser-action button click, it is advisable to implement a little mechanism, where the background-page sends a message to the content-script asking it to re-enable itself. If the content-script is indeed injected but disabled, it should respond back (to confirm it got the message) and re-enable itself. If there is no response (meaning this is the first time the user clicks the button on this page, the background-page injects the content script.

• If it is likely for the content script to be enabled-disabled multiple times in a web-pages life-cycle, it would be more efficient to "hide" the <div> instead of removing it (e.g.: div.style.display = 'none';).

• If you only need to disable event handler, instead of using the enabled flag, it is probably more efficient to keep a reference to the listener you want to disable and call removeEventListener().

E.g.:

function clickListener(evt) {
    evt.preventDefault();
    ...
}
document.addEventListener('click', clickListener);

/* In order to "disable" the content-script: */
div.parentNode.removeChild(div);
document.removeEventListener('click', clickListener);