Front end sort order example - the jQuery part

/*!
 * A set of JS and jQuery functions/executions. For plugins, see plugins.min.js.
 */

// This allows quick retrieval of URL parameters
function GetURLParameter(sParam) {
    var sPageURL = window.location.search.substring(1);
    var sURLVariables = sPageURL.split('&');
    for (var i = 0; i < sURLVariables.length; i++)
    {
        var sParameterName = sURLVariables[i].split('=');
        if (sParameterName[0] == sParam)
        {
            return sParameterName[1];
        }
    }
}

jQuery(function($) {

    /** This function sets the up & down arrow & sort parameters on click in the front end **/

    // Set variables for possible URL parameters used in the script
    var orderby = GetURLParameter('orderby');
    var order = GetURLParameter('order');
    var active = GetURLParameter('active');

    // Now that we know what parameters are used, let's build our output string. Note that
    // we don't care about the "order" parameter because we're building this to control the
    // arrow itself -- it's manually assigned in the switch (later).
    function BuildURL() {
        var findParams = [];
        var iteration = 0;
        var target = "";

        // Find out which params are defined and build the full strings into an array
        if(typeof (orderby) != 'undefined' && orderby != null ) {
            findParams.push("orderby=" + orderby);
        }
        if(typeof (active) != 'undefined' && orderby != null ) {
            findParams.push("active=" + active);
        }

        // Loop over the array and insert the appropriate separators
        $.each(findParams, function(key,value) {
            iteration++;
            if ( iteration === 1 ) {
                target += "?";
            } else {
                target += "&";
            }
            target += value;
        });

        // Set final seperators depending on what was defined then return the result
        if(typeof (target) != 'undefined' && target != '' && target != null) {
            target = target + "&";
            return target;
        } else {
            target = "?";
            return target;
        }
    }

    // Grab the sort buttons for manipulation
    var sortBar = $('.sortbar');
    var sortButton = sortBar.find('div');
    var byPrice = $('div.byprice');
    var theURL = window.location.href.split('?');

    // Check which button is active and add it to a variable
    switch(orderby) {
        case 'property_price' :
            byPrice.addClass('active');
            break;
        case 'property_revenue' :
            $('.byrev').addClass('active');
            break;
        case 'adjusted_sde' :
            $('.bysde').addClass('active');
            break;
        default :
            // default sort is by price
            byPrice.addClass('active');
    }

    // On the active button, check the sort order
    var activeSort = sortButton.find('.active');

    switch(order) {
        case 'asc' :
            sortBar.find('.active').find('i').removeClass('fa-sort-desc').addClass('fa-sort-asc');
            sortBar.find('.active').find('a').attr('href', theURL[0] + BuildURL() + "order=desc");
            break;
        case 'desc' :
            sortBar.find('.active').find('a').attr('href', theURL[0] + BuildURL() + "order=asc");
            break;
        default :
            sortBar.find('.active').find('a').attr('href', theURL[0] + BuildURL() + "order=asc");
    }
});