How do I make a Javascript alert display only once, ever? [closed]

Answer 1

one is NOT what you need as a page refresh will override all the 'memory'.

You are most likely looking for localStorage or, if you are using internet explorer prior to version 8, use cookies:

    <script type="text/javascript">
        var alerted = localStorage.getItem('alerted') || '';
        if (alerted != 'yes') {
         alert("You are using Internet Explorer to view this webpage.  Your experience may be subpar while using Internet Explorer; we recommend using an alternative internet browser, such as Chrome or Firefox, to view our website.");
         localStorage.setItem('alerted','yes');
        }
    </script>

EDIT:

For IE versions prior to 8 you need to use cookies, since there is not suppor for localStorage. It's the exact same concept, just different methods. Take a look at this question for implementing cookies on your page.

After you copied the code from the example, you should have 2 functions - createCookie() and getCookie().

var createCookie = function(name, value, days) {
....
//copy it from the other question
..
}

function getCookie(c_name) {
....
//copy it from the other question
..
}

<!--[if IE]>  
    <script type="text/javascript">
                var alerted = getCookie('alerted') || '';
                if (alerted != 'yes') {
                 alert("You are using Internet Explorer to view this webpage.  Your experience may be subpar while using Internet Explorer; we recommend using an alternative internet browser, such as Chrome or Firefox, to view our website.");
                 createCookie('alerted','yes',365);//cookies expires after 365 days
                }
            </script>
<![endif]-->

Hope this helps!