javascript 模板系统 ejs v6
此版本有如下改进：
- 吸取众人的意见，防止与ASP等后台模板的界定符冲突，默认左右界定符为<&，&>
- 加入新的操作符<&~，至此整个操作符体系为:
<& JS逻辑 &> <& for(var i=0,tl = @trs.length,tr;i < tl;i++){ &> <&= JS输出内容 &> <&= tr.name &> <&# 这是注释 &> <&# 导入子模板 &> <&: CSS选择符 &> <&: tds_tmpl &> <&~ URL地址 &> <&~ /aaa/bbb.html &> - 为了迎合大规模开发的需要，后台数据统统增加@标识，一来便于修改，二来内部实现抛弃了with语句，强行让它们依附于data对象，让我们可以使用||设置默认值。
//dom.ejs v6 by 司徒正美
//http://www.cnblogs.com/rubylouvre/archive/2010/10/04/1841933.html
;(function(){
this.dom = {
quote : String.quote || function (str) {
str = str.replace(/[\x00-\x1f\\]/g, function (chr) {
var special = metaObject[chr];
return special ? special : '\\u' + ('0000'+chr.charCodeAt(0).toString(16)).slice(-4);
});
return '"' + str.replace(/"/g, '\\"') + '"';
}
}
if(!String.prototype.trim){
String.prototype.trim = function(){
return this.replace(/^[\s\xa0]+|[\s\xa0]+$/g, '');
}
}
;(function(w,s){
//http://blogs.msdn.com/xmlteam/archive/2006/10/23/using-the-right-version-of-msxml-in-internet-explorer.aspx
s = ["XMLHttpRequest",
"ActiveXObject('Msxml2.XMLHTTP.6.0')",
"ActiveXObject('Msxml2.XMLHTTP.3.0')",
"ActiveXObject('Msxml2.XMLHTTP')",
"ActiveXObject('Microsoft.XMLHTTP')"];
//IE专有的JScript方法：ScriptEngine，ScriptEngineBuildVersion，ScriptEngineMajorVersion，ScriptEngineMinorVersion，CollectGarbage，RuntimeObject和GetObject。
if( !-[1,] && w.ScriptEngineMinorVersion() === 7 && location.protocol === "file:"){
s.shift();
}
for(var i = 0 ,el;el=s[i++];){
try{
if(eval("new "+el)){
dom.xhr = new Function( "return new "+el);
break;
}
}catch(e){}
}
})(window);
var
metaObject = {
'\b': '\\b',
'\t': '\\t',
'\n': '\\n',
'\f': '\\f',
'\r': '\\r',
'\\': '\\\\'
},
_startOfHTML = "\t__views.push(",
_endOfHTML = ");\n",
_rAt = /(^|[^\w\u00c0-\uFFFF_])(@)(?=\w)/g,
_partial = function(url){
var xhr = dom.xhr();
xhr.open("GET",url,false);
xhr.setRequestHeader("If-Modified-Since","0");
xhr.send(null);
return xhr.responseText|| ""
}
dom.ejs = function(obj,usePart){
if(!usePart){//如果普通模板，则要整理配置文件
obj.left = obj.left || "<&";
obj.right = obj.right || "&>";
obj.rLeft = obj.rLeft || new RegExp("\\s*"+ obj.left+"\\s*");
obj.rRight = obj.rRight || new RegExp("\\s*"+ obj.right+"\\s*");
}
var key = obj.selector || obj.url,
rAt = _rAt,
startOfHTML = _startOfHTML,
endOfHTML = _endOfHTML,
partial = _partial,
self = arguments.callee,
buff = ["var __views = [];\n"],str,logic;
if(obj.selector){
var el = document.getElementById(key);
if (!el) throw "can not find the target element";
str = el.text;
}else {
str = partial(obj.url);
if (!str) throw "the target file does not exist";
}
if(!self[key]){
var arr = str.trim().split(obj.rLeft),temp = [],url,selector,i=0,n=arr.length,els,segment;
while(i<n){
segment = arr[i++];
els = segment.split(obj.rRight);
if(segment.indexOf(obj.right) !== -1){//这里不使用el.length === 2是为了避开IE的split bug
switch (els[0].charAt(0)) {
case "~"://include局部模板 以URL方式引入
delete obj.selector;
obj.url = els[0].substring(1).trim();
self[url] = self[url] || self(obj,true);
temp = temp.concat(self[url] );
break;
case ":"://include局部模板 以元素选择符方式引入
delete obj.url;
selector = obj.selector = els[0].substring(1).trim();
self[selector] = self[selector] || self(obj,true);
temp = temp.concat(self[selector] );
break;
case "="://处理后台返回的变量（输出到页面的);
logic = els[0].substring(1);
if(logic.indexOf("@")!==-1){
temp.push(startOfHTML, logic.replace(rAt,"$1data."), endOfHTML);
}else{
temp.push(startOfHTML, logic, endOfHTML);
}
break;
case "#"://处理注释
break;
default://处理逻辑
logic = els[0];
if(logic.indexOf("@")!==-1){
temp.push(logic.replace(rAt,"$1data."), "\n");
}else{
temp.push(logic, "\n");
}
}
//处理静态HTML片断
els[1] && temp.push(startOfHTML, dom.quote.call(null,els[1]), endOfHTML)
}else{
//处理静态HTML片断
temp.push(startOfHTML, dom.quote.call(null,els[0]), endOfHTML)
}
}
if(usePart){//局部模板
return (self[key] = temp);
}else{
self[key] = new Function("data",buff.concat(temp).join("")+';return __views.join("");');
}
}
return self[key](obj.data || {});
}
})();
重申一次，并不是前台模板系统无能，只是你我做的项目不同，访问量大小决定着代码需要用另一种截然不同的方式实现。我想到一个例子，就是腾讯的QQ群，里面80%的内容都是JS模板。