chrome.tabs.onUpdated.addListener(function(id, info, tab) {
  if (tab.url.toLocaleLowerCase().indexOf("banweb.pdx.edu") > -1) {
    chrome.pageAction.show(tab.id);
    chrome.tabs.executeScript(null, {"file": "extension.js"});
  }
});
@@ -117,16 +117,45 @@
 u%22) %3E -1
+ && info.status === 'loading'
 ) %7B%0A    
@@ -220,12 +220,14 @@
 ipt(
-null
+tab.id
 , %7B%22

add script tab id and status checking