javascript - Mobile Safari back button

Question

(This question already has answers here): question from:https://stackoverflow.com/questions/11979156/mobile-safari-back-button

Answer 1

This is caused by back-forward cache. It is supposed to save complete state of page when user navigates away. When user navigates back with back button page can be loaded from cache very quickly. This is different from normal cache which only caches HTML code.

When page is loaded for bfcache onload event wont be triggered. Instead you can check the persisted property of the onpageshow event. It is set to false on initial page load. When page is loaded from bfcache it is set to true.

window.onpageshow = function(event) {
    if (event.persisted) {
        alert("From back / forward cache.");
    }
};

For some reason jQuery does not have this property in the event. You can find it from original event though.

$(window).bind("pageshow", function(event) {
    if (event.originalEvent.persisted) {
      alert("From back / forward cache.");
    }
});

Quick solution to these problem is to reload the page when back button is pressed. This however nullifies any positive effect back / forward cache would give.

window.onpageshow = function(event) {
    if (event.persisted) {
        window.location.reload() 
    }
};

As a sidenote, you can see lot of pages offering using empty onunload handler as solution. This has not worked since iOS5.

$(window).bind("unload", function() { });