Appendix JS_N_A6

Requirement: Changes of context are only initiated by user request or with user control.

Details: Do not automatically refresh the page without user confirmation or control.

<form id="demo" action="#">
    <fieldset>
        <legend><strong>Refresh the page ...</strong></legend>
        <p>
            <input id="refresh0" name="refresh" 
                value="0" type="radio" checked="checked" />
            <label for="refresh0">Never</label>
        </p>
        <p>
            <input id="refresh30" name="refresh" 
                value="30" type="radio" />
            <label for="refresh30">Every 30 seconds</label>
        </p>
        <p>
            <input id="refresh60" name="refresh" 
                value="60" type="radio" />
            <label for="refresh60">Every minute</label>
        </p>
        <p>
            <input id="refresh300" name="refresh" 
                value="300" type="radio" />
            <label for="refresh300">Every 5 minutes</label>
        </p>
        <p>
            <input id="refresh900" name="refresh" 
                value="900" type="radio" />
            <label for="refresh900">Every 15 minutes</label>
        </p>
    </fieldset>
    <fieldset>
        <button type="submit">Save and Refresh</button>
    </fieldset>
</form>

var form = document.getElementById('demo');
var radios = form.refresh;
var cookiename = 'page_refresh_time';
 
if(document.cookie.indexOf(cookiename) != -1)
{
    var refreshtime = document.cookie
        .split(cookiename + '=')[1]
        .split(';')[0]
        .split('=')[0];
 
    for(var i = 0; i < radios.length; i ++)
    {
        if(radios[i].value == refreshtime)
        {
            radios[i].checked = true;
            break;
        }
    }
 
    var milliseconds = parseInt(refreshtime, 10) * 1000;
    if(milliseconds > 0)
    {
        window.setTimeout(function()
        {
            document.location.reload();
 
        }, milliseconds);
    }
}
 
form.addEventListener('submit', function(e)
{
    for(var i = 0; i < radios.length; i ++)
    {
        if(radios[i].checked)
        {
            var now = new Date();
            now.setTime(
                now.getTime() 
                + (365 * 24 * 60 * 60 * 1000));
 
            document.cookie = cookiename 
                + '=' + radios[i].value 
                + '; expires=' + now.toGMTString()
                + '; path=/';
 
            document.location.reload();
        }
    }
 
    e.preventDefault();
 
}, false);