Get Value from Query String HTML/JavaScript

Hi All,

Code below for Getting HTML/Javascript Value from QueryString


            var getQueryString = function (field) {
                var href = decodeURIComponent(window.location.href);
                var reg = new RegExp('[?&]' + field + '=([^&#]*)', 'i');
                var string = reg.exec(href);
                return string ? string[1] : null;
            };

var ContactID = getQueryString('contact');