Get Query String for current page as object

window.query.js

(function (window) {

    //declare the variables here, 
    //as js variable hoisting will do this
    //here anyway    
    var m, queryString, re;

    //if the window query object does not exist
    if (!window.query) {
    
        //create it
        window.query = {};
        
        //get the query string (without the #)
        queryString = location.search.substring(1);
        
        //declare the regex
        re = /([^&=]+)=([^&]*)/g

        //execute the regex for each query parameter
        while (m = re.exec(queryString)) {            
            //add the query parameter to the query object
            window.query[decodeURIComponent(m[1])] = decodeURIComponent(m[2]);
        }
    }
    
}(window));

Using regex for this is just wrong and will fail in some scenarios.

You'd better off using a tiny reusable module like:
https://github.com/sindresorhus/query-string