setGetParameter

/*
*   Adds or changes a GET parameter
*   See http://stackoverflow.com/a/13064060/703581
*   Adapted to handle '#' in the URL
*/
function setGetParameter(paramName, paramValue)
{
    var url = window.location.href;
    var splitAtAnchor = url.split('#');
    url = splitAtAnchor[0];
    var anchor = typeof splitAtAnchor[1] === 'undefined' ? '' : '#' + splitAtAnchor[1];
    if (url.indexOf(paramName + "=") >= 0)
    {
        var prefix = url.substring(0, url.indexOf(paramName));
        var suffix = url.substring(url.indexOf(paramName));
        suffix = suffix.substring(suffix.indexOf("=") + 1);
        suffix = (suffix.indexOf("&") >= 0) ? suffix.substring(suffix.indexOf("&")) : "";
        url = prefix + paramName + "=" + paramValue + suffix;
    }
    else
    {
    if (url.indexOf("?") < 0)
        url += "?" + paramName + "=" + paramValue;
    else
        url += "&" + paramName + "=" + paramValue;
    }
    window.location.href = url + anchor;
}