防止加载第二个静态HTML页面

Question

I have a link on a page. When the user clicks the link a static HTML page loads. I would like to prevent the user from launching a second instance of the same static HTML document.

I'm thinking some javascript up front in the static HTML page might do. Basically if the script detects that there is already an instance of the static HTML document loaded then a Javascript pop-up would indicate to the user that 'document is already loaded" (something like that).

Anyhow, Java script is not my strong point so wondering if someone can please shed some light on this.

Answer 1

I'm not sure if this is cross-browser, but works in Chrome:

var wins = {};
var anchors = document.getElementsByTagName('a');
for(var i=0, len=anchors.length; i<len; i++) {
    anchors[i].onclick = function(e) {
        e.preventDefault();
        var href = this.href;
        if(wins[href]) {
            wins[href].focus();
        } else {
            wins[href] = window.open(href);
        }

    }
}

http://jsbin.com/ivabax/1/edit

Answer 2

You could implement a logging feature that tracks each link that was clicked and maintains a session for the current user. If the link has already been clicked then you could present your firewall window that says "Sorry, this link has already been accessed".

So the hyperlink the user would click would first hit a tracking mechanism before being allowed (or not allowed) to continue to the URL in question.