JAvascriptページhead内にstyleを動的に挿入

        var css = 'h1 { background: red; }',

        head = document.getElementsByTagName('head')[0],

        style = document.createElement('style');

        style.type = 'text/css';

        if(style.styleSheet){

        style.styleSheet.cssText = css;

        }else{

        style.appendChild(document.createTextNode(css));

        }

        head.appendChild(style);

        var $style = $('<style type="text/css"></style>');

        $($('head')[0]).append($style);

        $style.append('.test{background: red;}');