CODEWITHSUNDEEP
javascripthtmlevent-handlingdom-eventsaddeventlistener
Ken
Ken

Reputation: 2734

HTML5 / JS storage event handler

I'm using Safari webkit's engine together with HTML5 and JS to create an offline application now I'm using the sessionStorage array to store status of my application(simulation).

The storage data works fine with the inspector the functions work fine it's the event handler that isn't responding.

The test preformd by Anurag at http://jsfiddle.net/pvRgH/ also doesn't work here:

window.addEventListener('storage', storageEventHandler, false);
function storageEventHandler(evt){
    alert("storage event called key: " + evt.key );
    switch(evt.key){
        case 'bat1':
        case 'bat2': batteryDCMeter(); break;
        case 'extPowerOn': rechargeBattery(); break;
    }   
}

function load()
{
    dashcode.setupParts();
    //set HTML 5 key/value's
    sessionStorage.setItem('bat1', 'OFF');
    sessionStorage.setItem('bat2', 'OFF');
    sessionStorage.setItem('bat1DC', '26.2');
    sessionStorage.setItem('bat2DC', '26.2');
}

function bat1OnOff(event)
{
    if(sessionStorage['bat1'] == 'OFF'){
        sessionStorage['bat1'] = 'ON';
    }else{
        sessionStorage['bat1'] = "OFF";
    }
}


function bat2OnOff(event)
{
    if(sessionStorage['bat2'] == 'OFF'){
        sessionStorage['bat2'] = 'ON';
    }else{
        sessionStorage['bat2'] = "OFF";
    }
}

Upvotes: 10

Views: 28095

Answers (4)

Mustkeem K
Mustkeem K

Reputation: 8768

To communicate between multiple tabs we can use storage event. You store a data item in local storage and you will get to know that your local storage is updated.

Check out the code.

      window.addEventListener("storage", storageEventHandler, false);

      function storageEventHandler(evt) {
        alert("storage updated");
      }

      function clickme() {
        localStorage.setItem("someKey", "someValue");
      }
<button onclick="clickme()">Click Me</button>

Note: storage event only fires in other tabs. Not inside the tab, you are in currently. click^ :)

Upvotes: 0

chenhui5416
chenhui5416

Reputation: 31

the 'storage' event occurred by the other tab in the browser. When you change the storage in one page and addEventLister also in this page , the window can not catch the message.

for example

You have two page, pageOne change the storage , pageTwo will catch the 'storage' message and handle this, but pageOne couldn't catch the message.

Upvotes: 1

jmease
jmease

Reputation: 2535

Storage event handlers only fire if the storage event is triggered from another window.

How can I get an event to fire every time localStorage is updated in Safari 5+?

Upvotes: 19

Anurag
Anurag

Reputation: 141879

Could you provide some more code for how you are storing the keys? It works for me on Safari - http://jsfiddle.net/pvRgH/

Upvotes: 0

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