SOW how to get url params ?

[KelvinY2025]

var url = new GlideURL(window.location.href);

var paramValue = url.getParam('myparam');

if (paramValue) {

   console.log('Parameter exists with value:', paramValue);

} else {

   console.log('Parameter does not exist.');

}

(g_env) [SCRIPT:EXEC] Error while running Client Script "Incident Demo01": ReferenceError: GlideURL is not defined

why ?  How to do ?