Grooveshark Chrome Extension

gs.js

chrome.extension.onRequest.addListener(
    function(request, sender, sendResponse) {
        switch (request.message.action){
            case "addSong" :
                Grooveshark.addSongsByID(request.message.ID, true);
                break;
            case "getSong" :
                var song = GrooveShark.getCurrentSongStatus().song;
                sendResponse({"songTitle": song});
                break;
        }
    }     
);

manifest.json

{
	"name": "Buzzedword Extension",
	"version": "1.0",
	"description": "Demo",
	"icons":{
		"128":"icon_128.png"
	},
	
	"browser_action":	{
		"default_icon": "icon.png",
		"popup": "empty.html"
	},
    "permissions": ["tabs", "http://grooveshark.com/*"],
    "content_scripts": [
        {
            "matches": ["http://grooveshark.com/*"],
            "js": ["gs.js"],
            "run_at": "document_end"
        }
    ]    
}

script.js

function GetChromeDomain(url){
    var parts, domainSplit, name;
        parts = url.split('/');
        domainSplit = parts[2].split(':');
        name = domainSplit[0];
        return name;
}

function startGS(tabID){
    chrome.tabs.sendRequest(tabID, {
        message : {
            action : "addSong",
            ID : "28102067"
        }
    });
}
chrome.windows.getCurrent( function(Window){
    chrome.tabs.getAllInWindow(Window.id, function(tabs){
        var gsTab;
        for (var i in tabs){
            if (GetChromeDomain(tabs[i].url) == 'grooveshark.com'){
                gsTab = tabs[i].id;
            }
        }
        if (typeof gsTab != 'undefined'){
            startGS(gsTab);
        }
    });
});