JS to grab Get Paramert from URL

jsGetUrl.js

var getparams = function(param) {
    var url = window.location.search.substring(1);
    var urlvars = url.split('&');
    for (var i = 0; i < urlvars.length; i++) {
        var paramname = urlvars[i].split('=');
        if ( paramname[0] == param) {
            return paramname[1];
        }
    }
};

var param1 = getparams('param1');