javascript change get parameter without reload

function replaceQueryParam(param,newval,search){
	var regex=new RegExp("([?;&])"+param+"[^&;]*[;&]?");
	var query=search.replace(regex,"$1").replace(/&$/,'');
	return (query.length>2?query+"&":"?")+(newval?param+"="+newval:'');
}
var next_page=2;
var search_param=location.search;
search_param=replaceQueryParam('page',next_page,search_param);
var newurl=window.location.pathname+search_param;
window.history.pushState({path:newurl},'',newurl);