var doesn't exist in other functions (javascript & firefox extension)

Question

My firefox extension have to:

1. Save an address of current page,
2. Open new page
3. Put this address into content of the new page, if a button will be pressed.

Problem is, how to save to var this address, becouse if I will do it from first function, the function that is from button doesnt have this var. Should i use a global function, or something?

function openTab() {
  //Save an address of current page
  path=content.location.href;
  //Open new Tab and select it
  var tab=gBrowser.addTab("chrome://intabeditor/content/editor.html");
  var newTabBrowser = gBrowser.getBrowserForTab(tab);
  gBrowser.selectedTab=tab;
}

function write() {
  content.body.innerHTML=path;
}

Function openTab() is execute, when proper button is pressed, the same with write() function

Answer 1

var path = null;
function openTab() {
  //Save an address of current page
  path=content.location.href;
  //Open new Tab and select it
  var tab=gBrowser.addTab("chrome://intabeditor/content/editor.html");
  var newTabBrowser = gBrowser.getBrowserForTab(tab);
  gBrowser.selectedTab=tab;
}

function write() {
  if (path!=null)
    content.body.innerHTML=path;
}

---EDIT And this example? everything is encapsulated in xopen:

<script type="text/javascript">

    var xopen = function()
    {
     this.path = null;
     this.openTab = function()
     {
      //Save an address of current page
      this.path=content.location.href;
      //Open new Tab and select it
      var tab=gBrowser.addTab("chrome://intabeditor/content/editor.html");
      var newTabBrowser = gBrowser.getBrowserForTab(tab);
      gBrowser.selectedTab=tab; 
        }

     this.write = function () 
     {
      if (this.path!=null)
       content.body.innerHTML=this.path;
     }
    }
    var wopen = new xopen();

</script>
<button onclick="wopen.openTab()">openTab</button>
<button onclick="wopen.write()">write</button>