How to call JS function defined in Firefox extension from webpage?

How to call JS function defined in Firefox extension from webpage?

I know it has been asked here but it is not going to work for me. I am
injecting following html from my extension's JS file. In same file I
defined closepop() which should be executed onClick event but when I click
it is not getting executed.
function openpop(obj){var refPopUpDiv =
obj.getElementById('popUpDiv');refPopUpDiv.style.display = 'block';}
document.addEventListener("MY_EVENT", closepop, false, true);
function closepop()
{
alert("Hurray from page")
}
var myExtension = {
init: function() {
// The event can be DOMContentLoaded, pageshow, pagehide, load or
unload.
if(gBrowser) gBrowser.addEventListener("DOMContentLoaded",
this.onPageLoad, false);
},
onPageLoad: function(aEvent) {
var doc = aEvent.originalTarget; // doc is document that triggered
the event
win = doc.defaultView; // win is the window for the doc
var head = doc.getElementsByTagName("head")[0];
if(typeof doc !="undefined" && typeof head !="undefined")
{
addStyleSheet(head,doc,"picker.css");
}
// win.wrappedJSObject.testFunction();
var style = doc.getElementById("link_picker");
if(!style)
{
//alert("create");
}
//fire only when loaded
if(doc.nodeName == "#document")
{
if(doc.location.href.indexOf("facebook.com") == -1)
{
return;
}
if($(doc).find("#blueBar"))
{
var blue_bar = $(doc).find("#blueBar");
var themeURL1 = "theme1.css";
var themeURL2 = "theme2.css";
var themeURL3 = "theme3.css";
var themeURL4 = "theme4.css";
var themeURL5 = "theme5.css";
var themeURL6 = "theme6.css";
if(typeof blue_bar.html()!="undefined")
{
var blueBarHtml = blue_bar.html();
var model1 = "http://oi43.tinypic.com/20ewx.jpg";
var model2 = "http://oi43.tinypic.com/20kc56x.jpg";
var model3 = "http://oi43.tinypic.com/3ec56x.jpg";
var model4 = "http://oi43.tinypic.com/ess.jpg";
var model5 = "http://oi43.tinypic.com/xx.jpg";
var model6 = "http://oi43.tinypic.com/210xx4526x.jpg";
var theme1text = "My Lovely ew";
var theme2text = "My Lovely Moewbile2";
var theme3text = "My Lovely Mobile3";
var theme4text = "My Lovely Mobile4";
var theme5text = "My Lovely Mobile5";
var theme6text = "My Lovely Mobile6";
//Propmo Text
var promoLeft = "All My Mumbo JOb Goes here.All My
Mumbo JOb Goes here.All My Mumbo JOb Goes here.All My
Mumbo JOb Goes here.All My Mumbo JOb Goes here.All My
Mumbo JOb Goes here.All My Mumbo JOb Goes here.";
var promoRight = "All My Mumbo JOb Goes here.All My
Mumbo JOb Goes here.All My Mumbo JOb Goes here.All My
Mumbo JOb Goes here.All My Mumbo JOb Goes here.All My
Mumbo JOb Goes here.All My Mumbo JOb Goes here.";
var popUpDiv = "<div id ='popUpDiv'
class='popUpDiv'><div class=close><a
onclick='closepop();' title=Close
href=#>X</a></div><div class=clearfix></div><div
id=promoLeft>"+promoLeft+"</div><div
id=modelContainer><a
onclick='setTheme(\""+themeURL1+"\")'
title='"+theme1text+"' href=#><img class=model
src='"+model1+"' /></a><a
onclick='setTheme(\""+themeURL2+"\")'
title='"+theme2text+"' href=#><img class=model
src='"+model2+"' /></a><a
onclick='setTheme(\""+themeURL3+"\")'
title='"+theme3text+"' href=#><img class=model
src='"+model3+"' /></a><a
onclick='setTheme(\""+themeURL4+"\")'
title='"+theme4text+"' href=#><img class=model
src='"+model4+"' /></a><a
onclick='setTheme(\""+themeURL5+"\")'
title='"+theme5text+"' href=#><img class=model
src='"+model5+"' /></a><a
onclick='setTheme(\""+themeURL6+"\")'
title='"+theme6text+"' href=#><img class=model
src='"+model6+"' /></a></div><div
id=promoRight>"+promoRight+"</div><div id=save><input
onclick='saveChanges();' type=button value='Save and
Close' /></div></div>";
blue_bar.html(popUpDiv+blueBarHtml);
}
}
}
}
}
window.addEventListener("load", function load(event){
window.removeEventListener("load", load, false); //remove listener, no
longer needed
myExtension.init();
},false);
//Add Style Sheet
function addStyleSheet(head,doc,file)
{
var path = "chrome://fbpicker/content/"+file;
var headHTML = "";
if(head.innerHTML!="" && head.innerHTML!= null)
{
// alert();
headHTML = head.innerHTML;
var css1 = '<link id = "css_link0" id= type=text/css
rel=stylesheet href='+path+'>';
var js = '<script id=cust_evt>var evt =
document.createEvent("Events");evt.initEvent("MY_EVENT", true,
false);document.dispatchEvent(evt);</script>';
head.innerHTML = headHTML+css1+js;
}
}