There are some links on web-page.
On right click there is option of 'open link in new tab'(browser option).
I want to restrict user for not opening more that two tabs?
How can i do this?
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<ul>
<li><a href="http://localhost:8080/struts_tab/abcForm1.action" oncontextmenu="return false;"><span>First Click[Right Click disabled]</span></a></li>
<li><a href="http://localhost:8080/struts_tab/defForm2.action"><span>Second clieck[Not more than 2 tabs]</span></a></li>
</ul>
</body>
</html>
You can't restrict the user from opening a new tab.
(This reminds me the old pop-ups with no buttons, no address bar, but still responding to backspace and other events)
You can however make your app recognize the attempt of opening a third tab, and load a different result like an error message, for example:
Maximum open tabs limit reached. Please use no more than two tabs concurrently. close this tab
To do this, you can use HTML5 sessionStorage.
Note: Web Storage (sessionStorage and localStorage) is supported on every browser nowadays.
sessionStorage
This is a global object (sessionStorage) that maintains a storage area
that's available for the duration of the page session. A page session
lasts for as long as the browser is open and survives over page
reloads and restores. Opening a page in a new tab or window will cause
a new session to be initiated.
Then you can
if not present in sessionStorage, generate an unique token in JSP, and put it in sessionStorage,
$(function(){
// Read the ID. If it's null, this is a new tab:
// generate the ID and store it for later.
var tabId = sessionStorage.getItem("tabId");
if (tabId == null){
tabId = Math.random();
sessionStorage.putItem("tabId",tabId);
}
send it back to the action
// Add the ID to the form (as hidden field),
// so it will be posted back in next submission.
$('<input>').attr('type' , 'hidden')
.attr('name' , 'tabId')
.attr('value' , tabId)
.appendTo('form');
});
, maybe to a setter in a BaseAction, extendend by the other actions, and read by prepare(), or much better in an Interceptor;
put it in a collection checking that it doesn't contain already two elements, otherwise return the error result, that should be mapped globally:
public String intercept(ActionInvocation actionInvocation) throws Exception {
Action action = (Action) actionInvocation.getAction();
if(action instanceof LimitedTabsAware){ //interface to identify special actions
ActionContext context = actionInvocation.getInvocationContext();
Map<String, String[]> request = ((HttpServletRequest)
context.get(StrutsStatics.HTTP_REQUEST)).getParameterMap();
if (request.containsKey("tabId")){
String tabId = (String) request.get("tabId")[0];
List<String> openTabs = context.getSession().get("OPEN_TABS_KEY");
if (openTabs.contains(tabId)){
return actionInvocation.invoke();
} else if (openTabs.size()>=2){
return "tabLimitExceeded"; // global result
} else {
openTabs.add(tabId);
context.getSession().put("OPEN_TABS_KEY", openTabs);
return actionInvocation.invoke();
}
} else {
throw new IllegalArgumentException("There is no tabId in this request.");
}
} else {
return actionInvocation.invoke();
}
}
Then you should find a way to recognize when a tab get closed (to free one slot), by either:
- timizing the period of validity of the elements in your collection (if you don't use a tab for some time, the session expires, and so must do the token in the collection)
- otherwise, putting a javascript AJAX timer in your page (eg. every 30 seconds), that send a
keep-alive signal to an action to refresh the validity of the element. If the tab get closed, the signal is not sent anymore.
