I am trying to attempt my first Google Chrome Extension and have a question. My end goal is to be able to select a button which will perform the following:
- Grab the current URL of the selected tab (Ex: www.google.com) 
- Open a new tab using the URL from step 1 and appending a query string to the end (Ex: www.google.com?filter=0) 
Currently, I was able to figure out how to open a create a new tab which loads a specified URL. What I am unsure of how to detect the URL from the selected tab and load that value in the new tab. Suggestions? Thanks in advance!!
Code below:
[popup.html]
    <html>
<head>
<style>
body {
  min-width:175px;
  overflow-x:hidden;
}
</style>
<script>
 function createTab() {
  chrome.tabs.create({'url': 'http://www.google.com'});
 }
 function show_alert()
 {
 alert("I am an alert box!");
 }
</script>
</head>
<body>
<input type="button" onclick="createTab()" value="Create New Tab" />
<hr/>
<input type="button" onclick="show_alert()" value="Show alert box" />
</body>
</html>
[manifest.json]
{
  "name": "IGX Plugin",
  "version": "1.0",
  "description": "IGX Plugin",
  "browser_action": {
    "default_icon": "favicon.ico",
 "popup": "popup.html"
  },
  "permissions": [
    "tabs"
  ]
}
 
     
    