如何捕获URL参数并传递给url重定向

function getParameterByName(name, url) {
    if (!url) url = window.location.href;
    name = name.replace(/[\[\]]/g, '\\$&');
    var regex = new RegExp('[?&]' + name + '(=([^&#]*)|&|#|$)'),
        results = regex.exec(url);
    if (!results) return null;
    if (!results[2]) return '';
    return decodeURIComponent(results[2].replace(/\+/g, ' '));
}

var parameterValue = getParameterByName('parameterName');
var redirectUrl = 'https://example.com/redirect?parameterName=' + encodeURIComponent(parameterValue);
window.location.href = redirectUrl;