<script type="text/javascript">
        function loadCss(){
            var cssLink = document.createElement("link");
            cssLink.setAttribute("rel", "stylesheet");
            cssLink.setAttribute("type", "text/css");
            cssLink.setAttribute("href",  "http://localhost/demo/css.css");//CSS文件路径改成你自己的
            var main=window.frames[0].document;
            main.body.appendChild(cssLink);
        }
        window.onload=function(){        
            loadCss();
        }
    </script>