how to catch a state change event ONCE with history.js?

I have an example code below where if you click the links, then use back and forward, each state change will cause more and more hits on the 'statechange' event. Instead of the one that I expect.

Links:

Code:

<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>History start</title>
</head>
<body>
    <h1>Headline</h1>
    <hr>
    <div id="menu">
        <ul>
            <li>
                <a href="page-1">Page 1</a>
                <div style="display:none;">
                    <h2>Page 1</h2>
                    <p>Content 1</p>
                </div>
            </li>
            <li>
                <a href="page-2">Page 2</a>
                <div style="display:none;">
                    <h2>Page 2</h2>
                    <p>Content 2</p>
                </div>
            </li>
        </ul>
    </div>
    <hr>
    <div id="content">
        <h2>Start page</h2>
        <p>Paragraf</p>
    </div>
    <script src="external/jquery-1.6.2.min.js"></script>
    <script>if ( typeof window.JSON === 'undefined' ) { console.log("Loaded json2"); document.write('<script src="external/json2.js"><\/script>'); }</script>
    <script src="external/history.adapter.jquery.js"></script>
    <script src="external/history.js"></script>
    <script>
    $(document).ready(function() {
        History.enabled = true;

        $('a').each(function() {
            $(this).click(function(e) {
                e.preventDefault();
                var $link = $(e.target),
                    state = {'href': $link.attr('href'), 'title': $link.html()},
                    $div = $link.siblings('div'),
                    content = $div.html();

                $('#content').html(content);

                History.pushState(state, state.title, state.href);

                return false;
            });
        });

        History.Adapter.bind(window, 'statechange', function() {
            var State = History.getState();
            // remove double hit on event
            console.log(State);

        });

    });
    </script>
</body>
</html>

It's because you're calling the pushState function when you load the page, which also causes a statechange. I was in a similar situation and used a but a boolean before my pushStates so I knew I was doing a pushState. It looks like this...

historyBool = true;
History.Adapter.bind(window,'statechange',function(){ // Note: We are using statechange instead of popstate

var State = History.getState(); // Note: We are using History.getState() instead of event.state

    //don't run our function when we do a pushState
    if(historyBool){
        historyBool = false;
        tempFunction = new Function(State.data.ajaxRunFunction);
        tempFunction();
    }
    historyBool = true;
});

historyBool = false;
historySet = {ajaxRunFunction: "upc('" + pageID + "','')"};
History.pushState(historySet,"","");

While not relevant to your specific problem, I had a scenario where I needed to unbind the event handler from the History Adapter. To do so you can unbind the "statechange" event from window, which is what History.Adapter binds to when you call History.Adapter.bind() :

$(window).unbind('statechange.namespace');

You can added a namespace to the event to avoid unbinding other unrelated event handlers as above, or use a named function to unbind that function specifically. To use the above namespace, you would need to bind the handler using the same namespace, ie

History.Adapter.bind(window,'statechange.namespace',function(){...}

来源：https://stackoverflow.com/questions/7751263/how-to-catch-a-state-change-event-once-with-history-js

标签

javascript

ajax

javascript-events

browser-history

history.js