js-动态加载js和css

function loadjscssfile(filename,filetype){
    if(filetype == "js"){
        var fileref = document.createElement('script');
        fileref.setAttribute("type","text/javascript");
        fileref.setAttribute("src",filename);
    }else if(filetype == "css"){
        var fileref = document.createElement('link');
        fileref.setAttribute("rel","stylesheet");
        fileref.setAttribute("type","text/css");
        fileref.setAttribute("href",filename);
    }
   if(typeof fileref != "undefined"){
        document.getElementsByTagName("head")[0].appendChild(fileref);
    }
}

loadjscssfile("resources/css/z/480.css", "css");