name: ‘underscoreTemplate‘,        tester: function () {            var source = document.getElementById(‘underscoreTemplate‘).innerHTML;            var fn = _.template(source);            for (var i = 0; i < number; i ++) {                fn(data);            }        }

// 数据量var length = 100;// 渲染次数var number = 10000;var data =http://www.mamicode.com/ {    list: []};for (var i = 0; i < length; i ++) {    data.list.push({        index: i,        user: ‘<strong style="color:red">糖饼</strong>‘,        site: ‘http://www.planeart.cn‘,        weibo: ‘http://weibo.com/planeart‘,        QQweibo: ‘http://t.qq.com/tangbin‘      }); };

<!-- underscore 的模板 --><script id="underscoreTemplate" type="text/tmpl"><ul>    <% for (var i = 0, l = list.length; i < l; i ++) { %>        <li>用户: <%=list[i].user%>/ 网站：<%=list[i].site%></li>    <% } %></ul></script>

    // JavaScript micro-templating, similar to John Resig‘s implementation.    // Underscore templating handles arbitrary delimiters, preserves whitespace,    // and correctly escapes quotes within interpolated code.    // NB: `oldSettings` only exists for backwards compatibility.    // template本身是一个方法，可以提供三个参数，第一个为模板文本，第二个为对应模板数据，第三个为基本配置信息    //模板函数可以使用 <%= … %>插入变量, 也可以用<% … %>执行任意的 JavaScript 代码、进行HTML转义,使用<%- … %>    _.template = function(text, settings, oldSettings) {        if (!settings && oldSettings) settings = oldSettings;        settings = _.defaults({}, settings, _.templateSettings);        // Combine delimiters into one regular expression via alternation.        var matcher = RegExp([            (settings.escape || noMatch).source, (settings.interpolate || noMatch).source, (settings.evaluate || noMatch).source        ].join(‘|‘) + ‘|$‘, ‘g‘);        // Compile the template source, escaping string literals appropriately.        var index = 0;        var source = "__p+=‘";        //没有设置settings.variable 默认使用对象+. 来取值        var settingObj = !!settings.variable ? ‘‘ : ‘_obj.‘;        //几个分组        text.replace(matcher, function(match, escape, interpolate, evaluate, offset) {            source += text.slice(index, offset).replace(escaper, escapeChar);            index = offset + match.length;            if (escape) {                //编码                //_obj.XXX                source += "‘+\n((__t=(" + settingObj + escape.trim() + "))==null?‘‘:_.escape(__t))+\n‘";            } else if (interpolate) {                //取值                //_obj.XXX                source += "‘+\n((__t=(" + settingObj + interpolate.trim() + "))==null?‘‘:__t)+\n‘";            } else if (evaluate) {                //任意的Javascript                source += "‘;\n" + evaluate + "\n__p+=‘";            }            // Adobe VMs need the match returned to produce the correct offest.            return match;        });        source += "‘;\n";        // If a variable is not specified, place data values in local scope.        // 据说使用with 性能不咋地，可以使用变量
        // with可能会影响性能，并造成难以发现的错误        //if (!settings.variable) source = ‘with(obj||{}){\n‘ + source + ‘}\n‘;        //去掉使用with        if (!settings.variable) source = ‘ var _obj=obj||{};\n‘ + source + ‘ \n‘;        source = "var __t,__p=‘‘,__j=Array.prototype.join," +            "print=function(){__p+=__j.call(arguments,‘‘);};\n" +            source + ‘return __p;\n‘;        try {            var render = new Function(settings.variable || ‘obj‘, ‘_‘, source);        } catch (e) {            e.source = source;            throw e;        }        var template = function(data) {            return render.call(this, data, _);        };        // Provide the compiled source as a convenience for precompilation.        var argument = settings.variable || ‘obj‘;        template.source = ‘function(‘ + argument + ‘){\n‘ + source + ‘}‘;        return template;    };