How to replace the "document.URL.parseQuery()"

[Sai18]

I have to replace "document.URL.parseQuery()" due to DOM manipulation issue from the below script, Please suggest

function onLoad() {

   //Type appropriate comment here, and begin script below

    var av = getParmVal('sys_u_assignment_verified');

    var val=g_form.getValue('u_assignment_verified');

//  alert(val);

   if(av=='date' && (val==null || val=='')){

       var ga = new GlideAjax('needdate');

         ga.addParam("sysparm_name", "ndate");

         ga.getXML(function getResponse(response) {

             var s = response.responseXML.documentElement.getAttribute('answer').toString();

                         g_form.setValue('u_assignment_verified',s);

                         alert("Your asset assignment was successfully verified \n \n Note: Please update the Work Notes field and click the Update button to commit your Assignment Verification Process");      

   });

   }

}

function getParmVal(name){

    var url = document.URL.parseQuery();

    if(url[name]){

        return decodeURI(url[name]);

    }

    else{

        return;

    }

}