I am getting an error in internet explorer 11

"Unable to get property 'length' of undefined or null reference" on line

if (window.localStorage.length !== 0)

it works fine on chrome and Firefox, not sure whats causing it

<script>
    function initialize() {
        // test to see if brouser supports storeage api
        var bSupportsLocal = (('localStorage' in window) && window.localStorage !== null );

        if (!bSupportsLocal) {
            document.getElementById('infoform').innerHTML = "<p> Sorry, This browser does not suport local storage. </p>";
            return;
        }

        if (window.localStorage.length !== 0) {
        document.getElementById('firstName').value = window.localStorage.getItem('firstName');
        $.mobile.navigate("#benefits-facts");
        }
    }

    function storeLocalContent(fName) {
        window.localStorage.setItem('firstName', fName);

        }

        function clearLocalContent(strToStore) {
            window.localStorage.clear();

            }

    window.onload = initialize;
    </script> 

I am getting an error in internet explorer 11

"Unable to get property 'length' of undefined or null reference" on line

if (window.localStorage.length !== 0)

it works fine on chrome and Firefox, not sure whats causing it

<script>
    function initialize() {
        // test to see if brouser supports storeage api
        var bSupportsLocal = (('localStorage' in window) && window.localStorage !== null );

        if (!bSupportsLocal) {
            document.getElementById('infoform').innerHTML = "<p> Sorry, This browser does not suport local storage. </p>";
            return;
        }

        if (window.localStorage.length !== 0) {
        document.getElementById('firstName').value = window.localStorage.getItem('firstName');
        $.mobile.navigate("#benefits-facts");
        }
    }

    function storeLocalContent(fName) {
        window.localStorage.setItem('firstName', fName);

        }

        function clearLocalContent(strToStore) {
            window.localStorage.clear();

            }

    window.onload = initialize;
    </script> 

• javascript
• jquery
• internet-explorer-11

• didi you try to remove one equal sign? window.localStorage !== null – EugenSunic Commented Aug 9, 2015 at 21:21
• if i remove one equal sign i get "Sorry, This browser does not support local storage." – brodster Commented Aug 9, 2015 at 21:37
• I believe this could help you: stackoverflow./questions/21155137/… – EugenSunic Commented Aug 9, 2015 at 21:52
• that is not the problem, I am running the latest versions of IE 11 – brodster Commented Aug 9, 2015 at 22:06
• @brodster Are you perhaps accessing the page with file://? Or, have you checked the document mode that's in use? The page may be running under a patibility mode that doesn't support web storage. – Jonathan Lonowski Commented Aug 10, 2015 at 2:31

1 Answer 1

I thought in IE window.localStorage is undefined initially. You are checking is localStorage in the window and its not null. So bSupportLocal is setting to true. Its executing window.localStorage.length statement. Undefined.length causing error. Here is the code

     var bSupportsLocal = window['localStorage'] || '';

If localStorage is having some value it will assign to bSupportsLocal, otherwise it is assigned with empty string.