JavaScript function to return a query string as an object

getQueryObj.js

function getQuery(query) {
    query = query || window.location.search;

    var queryString = {};
    var vars = query.split('&');
    for (var i = 0; i < vars.length; i++) {
        var pair = vars[i].split('=');
        pair[0] = decodeURIComponent(pair[0]);
        pair[1] = decodeURIComponent(pair[1]);
        // If first entry with this name
        if (typeof queryString[pair[0]] === 'undefined') {
            queryString[pair[0]] = pair[1];
            // If second entry with this name
        } else if (typeof queryString[pair[0]] === 'string') {
            queryString[pair[0]] = [queryString[pair[0]], pair[1]];
            // If third or later entry with this name
        } else {
            queryString[pair[0]].push(pair[1]);
        }
    }
    return queryString;
}