js 手动插入meta标签和script标签

        // 插入 meta 标签
        var oMeta = document.createElement('meta');
        oMeta.content = 'width=device-width, initial-scale=1.0, maximum-scale=1.0,minimum-scale=1.0, user-scalable=0';
        oMeta.name = 'viewport';
        document.getElementsByTagName('head')[0].appendChild(oMeta);
        // 插入 script 标签
        var script = document.createElement("script");
        script.type = "text/javascript";
        script.src = "index.js";
        document.getElementsByTagName('head')[0].appendChild(script);