Repository: coderLMN/framework-free-single-page-app Branch: master Commit: 284b6c0c07ea Files: 2 Total size: 32.4 KB Directory structure: gitextract_wwk_el2v/ ├── LICENSE └── README.md ================================================ FILE CONTENTS ================================================ ================================================ FILE: LICENSE ================================================ GNU GENERAL PUBLIC LICENSE Version 2, June 1991 Copyright (C) 1989, 1991 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. Preamble The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change free software--to make sure the software is free for all its users. This General Public License applies to most of the Free Software Foundation's software and to any other program whose authors commit to using it. (Some other Free Software Foundation software is covered by the GNU Lesser General Public License instead.) You can apply it to your programs, too. When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs; and that you know you can do these things. To protect your rights, we need to make restrictions that forbid anyone to deny you these rights or to ask you to surrender the rights. These restrictions translate to certain responsibilities for you if you distribute copies of the software, or if you modify it. For example, if you distribute copies of such a program, whether gratis or for a fee, you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights. We protect your rights with two steps: (1) copyright the software, and (2) offer you this license which gives you legal permission to copy, distribute and/or modify the software. Also, for each author's protection and ours, we want to make certain that everyone understands that there is no warranty for this free software. If the software is modified by someone else and passed on, we want its recipients to know that what they have is not the original, so that any problems introduced by others will not reflect on the original authors' reputations. Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that redistributors of a free program will individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be licensed for everyone's free use or not licensed at all. The precise terms and conditions for copying, distribution and modification follow. GNU GENERAL PUBLIC LICENSE TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION 0. This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under the terms of this General Public License. The "Program", below, refers to any such program or work, and a "work based on the Program" means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it, either verbatim or with modifications and/or translated into another language. (Hereinafter, translation is included without limitation in the term "modification".) Each licensee is addressed as "you". Activities other than copying, distribution and modification are not covered by this License; they are outside its scope. The act of running the Program is not restricted, and the output from the Program is covered only if its contents constitute a work based on the Program (independent of having been made by running the Program). Whether that is true depends on what the Program does. 1. You may copy and distribute verbatim copies of the Program's source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and give any other recipients of the Program a copy of this License along with the Program. You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee. 2. You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of these conditions: a) You must cause the modified files to carry prominent notices stating that you changed the files and the date of any change. b) You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License. c) If the modified program normally reads commands interactively when run, you must cause it, when started running for such interactive use in the most ordinary way, to print or display an announcement including an appropriate copyright notice and a notice that there is no warranty (or else, saying that you provide a warranty) and that users may redistribute the program under these conditions, and telling the user how to view a copy of this License. (Exception: if the Program itself is interactive but does not normally print such an announcement, your work based on the Program is not required to print an announcement.) These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it. Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program. In addition, mere aggregation of another work not based on the Program with the Program (or with a work based on the Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License. 3. You may copy and distribute the Program (or a work based on it, under Section 2) in object code or executable form under the terms of Sections 1 and 2 above provided that you also do one of the following: a) Accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or, b) Accompany it with a written offer, valid for at least three years, to give any third party, for a charge no more than your cost of physically performing source distribution, a complete machine-readable copy of the corresponding source code, to be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or, c) Accompany it with the information you received as to the offer to distribute corresponding source code. (This alternative is allowed only for noncommercial distribution and only if you received the program in object code or executable form with such an offer, in accord with Subsection b above.) The source code for a work means the preferred form of the work for making modifications to it. For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable. However, as a special exception, the source code distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable. If distribution of executable or object code is made by offering access to copy from a designated place, then offering equivalent access to copy the source code from the same place counts as distribution of the source code, even though third parties are not compelled to copy the source along with the object code. 4. You may not copy, modify, sublicense, or distribute the Program except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense or distribute the Program is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance. 5. You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Program or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, by modifying or distributing the Program (or any work based on the Program), you indicate your acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the Program or works based on it. 6. Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions. You may not impose any further restrictions on the recipients' exercise of the rights granted herein. You are not responsible for enforcing compliance by third parties to this License. 7. If, as a consequence of a court judgment or allegation of patent infringement or for any other reason (not limited to patent issues), conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Program at all. For example, if a patent license would not permit royalty-free redistribution of the Program by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Program. If any portion of this section is held invalid or unenforceable under any particular circumstance, the balance of the section is intended to apply and the section as a whole is intended to apply in other circumstances. It is not the purpose of this section to induce you to infringe any patents or other property right claims or to contest validity of any such claims; this section has the sole purpose of protecting the integrity of the free software distribution system, which is implemented by public license practices. Many people have made generous contributions to the wide range of software distributed through that system in reliance on consistent application of that system; it is up to the author/donor to decide if he or she is willing to distribute software through any other system and a licensee cannot impose that choice. This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License. 8. If the distribution and/or use of the Program is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Program under this License may add an explicit geographical distribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus excluded. In such case, this License incorporates the limitation as if written in the body of this License. 9. The Free Software Foundation may publish revised and/or new versions of the General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. Each version is given a distinguishing version number. If the Program specifies a version number of this License which applies to it and "any later version", you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation. 10. If you wish to incorporate parts of the Program into other free programs whose distribution conditions are different, write to the author to ask for permission. For software which is copyrighted by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software generally. NO WARRANTY 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. END OF TERMS AND CONDITIONS How to Apply These Terms to Your New Programs If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms. To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the "copyright" line and a pointer to where the full notice is found. {description} Copyright (C) {year} {fullname} This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Also add information on how to contact you by electronic and paper mail. If the program is interactive, make it output a short notice like this when it starts in an interactive mode: Gnomovision version 69, Copyright (C) year name of author Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details. The hypothetical commands `show w' and `show c' should show the appropriate parts of the General Public License. Of course, the commands you use may be called something other than `show w' and `show c'; they could even be mouse-clicks or menu items--whatever suits your program. You should also get your employer (if you work as a programmer) or your school, if any, to sign a "copyright disclaimer" for the program, if necessary. Here is a sample; alter the names: Yoyodyne, Inc., hereby disclaims all copyright interest in the program `Gnomovision' (which makes passes at compilers) written by James Hacker. {signature of Ty Coon}, 1 April 1989 Ty Coon, President of Vice This General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Lesser General Public License instead of this License. ================================================ FILE: README.md ================================================ # 开发无框架单页面应用 -- 老码农的祖传秘方 # ## 什么是单页面应用（SPA）？ [维基百科上的描述](http://en.wikipedia.org/wiki/Single-page_application )是这样的： ``` “A single-page application (SPA), is a web application or web site that fits on a single web page with the goal of providing a more fluid user experience akin to a desktop application.” ``` 也就是说，单页面应用是仅包含单个网页的应用，目的是为了提供类似于本地应用的流畅用户体验。 ## 需不需要框架？ 要实现单页面应用，现在已经有很多现成的框架了，比如`AngularJS`, `Ember.js`, `Backbone.js`等等。它们都是很全面的开发平台，为单页面应用开发提供了必需的页面模板、路径解析和处理、后台服务api访问、DOM操作等功能。 事实上，现代的web应用开发基本都离不开一个甚至多个框架，开发无框架应用的想法听起来蛮不靠谱的，对吧？ 但是我总觉得现在是时候抛弃框架了。前两年我都在用 `AngularJS` 做开发，可以说已经比较熟悉它了，我的第一个单页面应用就是在 `AngularJS` 的启发下做出来的。框架曾经是我的挚爱。 但是现在每次看着它们那庞大臃肿的身躯和晦涩的语法，我都有一种鸡肋的感觉。还有不同框架下各种工具、插件难以混用的现状，让我不得不经常需要自己写原生代码解决很多问题。时间长了，我自然冒出一个想法：“为啥不干脆抛弃框架，直接写原生代码呢？毕竟，框架也是原生代码写出来的嘛。” ## 怎么实现无框架SPA？ 无框架单页面应用看似可行，但难度有多大？我还是心里没底，需要一点理论依据给自己壮胆。所以我就在网上到处寻摸了一番，偶然找到了这篇 Google 工程师 Joe Gregorio 写的文章[《别再用JS框架了》](http://coderlmn.github.io/frontEndCourse/nomoreJSF.html )，里面的分析有一种与我心有戚戚的感觉，看完还给它翻译成中文了。 不过，他提出的方法是更超前的，例如 `imports` 和 `Polymer`，我曾经试过，印象中只有 Google 的 Chrome Canary 才有支持，而且要先在选项中打开一些试验功能，浏览器会变得不那么稳定。`X-Tag` 和 `Bosonic` 也要依赖于一个小的库。而我想做的是现在的浏览器就已经能支持的功能，用原生代码来实现。所以他这篇文章只能让我坚定方向，但是具体的做法还得靠自己去发现。 后来又看了几篇比较偏学术的文章，例如这篇 Mixu 写的[《Single page apps in depth》](http://singlepageappbook.com/single-page.html )，对我也不太适用。他的模板都需要先编译为JS对象存放，和 AngularJS 的方法类似，但我觉得在一个小规模应用里应该有更加优雅的实现方法。 找了好几天文档，我突然意识到自己浪费了不少时间。所谓理论依据应该是高层次的，解决可行性的问题，剩下的就是自己去想办法实现了。可行性不是明摆着的嘛，那么多框架不也是用原生代码实现的么？ 想到这儿，我就开始自己尝试了。前后一共只花了两三天时间，写出来一共一两百行JS，就基本解决了问题。其实把代码写完了回顾一下，这些方法都算不上什么创新，都是标准的东西而已。肯定有别人也这么做了，只是我不知道而已吧。 可能有读者看到这儿不耐烦了：`“Talk is cheap. Show me the code.”` 好吧，下面就是代码的描述。 ## 老码农的实现方法 ### 基础对象 首先是定义缺省的两个页面片段（缺省页面和出错页面，这两个页面是基础功能，所以放在库里）相关代码，对每个片段对应的 uri（例如 `home`）定义一个同名的对象，里面存放了对应的 html 片段文件路径、初始化方法。 ```javascript var home = {}; //default partial page, which will be loaded initially home.partial = "lib/home.html"; home.init = function(){ //bootstrap method //nothing but static content only to render } var notfound = {}; //404 page notfound.partial = "lib/404.html"; notfound.init = function(){ alert('URL does not exist. please check your code.'); } ``` 随后是全局变量，包含了 html 片段代码的缓存、局部刷新所在 div 的 DOM 对象和向后端服务请求返回的根数据（`rootScope`，初始化时未出现，在后面的方法中才会用到）： ```javascript var settings = {}; //global parameters settings.partialCache = {}; //cache for partial pages settings.divDemo = document.getElementById("demo"); //div for loading partials, defined in index.html ``` ### 主程序 下面就是主程序了，所有的公用方法打包放到一个对象 `miniSPA` 中，这样可以避免污染命名空间： ```javascript // Main Object here var miniSPA = {}; ``` 然后是 changeUrl 方法，对应在 `index.html` 中有如下触发定义： ```html ``` `onhashchange` 是在location.hash发生改变的时候触发的事件，能够通过它获取局部 url 的改变。在 `index.html` 中定义了如下的链接： ```html

Demo Contents:

Home (Default) POST request GET request Invalid url
``` 每个 uri 都以 `#` 号开头，这样就能被 `onhashchange` 事件抓取到。最后的 div 就是局部刷新的 html 片段嵌入的位置。 ```javascript miniSPA.changeUrl = function() { //handle url change var url = location.hash.replace('#',''); if(url === ''){ url = 'home'; //default page } if(! window[url]){ url = "notfound"; } miniSPA.ajaxRequest(window[url].partial, 'GET', '',function(status, page){ if(status == 404){ url = 'notfound'; //404 page miniSPA.ajaxRequest(window[url].partial,'GET','',function(status, page404){ settings.divDemo.innerHTML = page404; miniSPA.initFunc(url); //load 404 controller }); } else{ settings.divDemo.innerHTML = page; miniSPA.initFunc(url); //load url controller } }); } ``` 上面的代码先获取改变后的 url，先通过 `window[url]` 找到对应的对象（类似于最上部定义的 `home` 和 `notfound`），如对象不存在（无定义的路径）则转到 `404` 处理，否则通过 `ajaxRequest` 方法获取 `window[url].partial` 中定义的 html 片段并加载到局部刷新的div，并执行 `window[url].init` 初始化方法。 `ajaxRequest` 方法主要是和后端的服务进行交互，通过 `XMLHttpRequest` 发送请求（ `GET` 或 `POST`），如果获取的是 html 片段就把它缓存到 `settings.partialCache[url]` 里，因为 html 片段是相对固定的，每次请求返回的内容不会变化。如果是其他请求（比如向 Github 的 markdown 服务 POST 一个字符串）就不能缓存了。 ```javascript miniSPA.ajaxRequest = function(url, method, data, callback) { //load partial page if(settings.partialCache[url]){ callback(200, settings.partialCache[url]); } else { var xmlhttp; if(window.XMLHttpRequest){ xmlhttp = new XMLHttpRequest(); xmlhttp.open(method, url, true); if(method === 'POST'){ xmlhttp.setRequestHeader("Content-type","application/x-www-form-urlencoded"); } xmlhttp.send(data); xmlhttp.onreadystatechange = function(){ if(xmlhttp.readyState == 4){ switch(xmlhttp.status) { case 404: //if the url is invalid, show the 404 page url = 'notfound'; break; default: var parts = url.split('.'); if(parts.length>1 && parts[parts.length-1] == 'html'){ //only cache static html pages settings.partialCache[url] = xmlhttp.responseText; //cache partials to improve performance } } callback(xmlhttp.status, xmlhttp.responseText); } } } else{ alert('Sorry, your browser is too old to run this app.') callback(404, {}); } } } ``` 对于不支持 `XMLHttpRequest` 的浏览器（主要是 IE 老版本），本来是可以在 else 里加上 **xmlhttp = new ActiveXObject('Microsoft.XMLHTTP');** 的，不过，我手头也没有那么多老版本 IE 用于测试，而且老版本 IE 本来就是我深恶痛绝的东西，凭什么要支持它啊？所以就干脆直接给个 `alert` 完事。 `render` 方法一般在每个片段的初始化方法中调用，它会设定全局变量中的根对象，并通过 `refresh` 方法渲染 html 片段。 ```javascript miniSPA.render = function(url){ settings.rootScope = window[url]; miniSPA.refresh(settings.divDemo, settings.rootScope); } ``` 获取后端数据后，如何渲染 html 片段是个比较复杂的问题。这就是 DOM 操作了。总体思想就是从 html 片段的根部入手，遍历 DOM 树，逐个替换属性和文本中的占位变量（例如`` 和 `

{{emojis.key}}

`），匹配和替换是在 `feedData()` 方法中完成的。 对于 img 元素，src 属性一开始是未知的，也不能直接把变量定义到它里面，不然浏览器会报404错误，虽然不影响用户使用，但对于代码来说总归是不好看的。所以需要在获取了 `data-src` 属性值后再复制到 src 中去，这样一开始 `src` 属性是空的，就不会报错了。 这里最麻烦的是 `data-repeat` 属性，这是为了批量渲染格式相同的一组元素用的。比如从 Github 获取了全套的 emoji 表情，共计 888 个（也许下次升级到1000个），就需要渲染 888 个元素，把 888 个图片及其说明放到 html 片段中去。而 html 片段中对此只有一条定义： ```html ``` 等 888 个 emoji 表情来了之后，就要自动把 `
  • ` 元素扩展到 888 个。这就需要先 `clone` 定义好的元素，然后根据后台返回的数据逐个替换元素中的占位变量。 ```javascript miniSPA.refresh = function(node, scope) { var children = node.childNodes; if(node.nodeType != 3){ //traverse child nodes, Node.TEXT_NODE == 3 for(var k=0; k')+'","mode": "gfm","context": "github/gollum"}'; miniSPA.ajaxRequest('https://api.github.com/markdown', 'POST', data,function(status, page){ document.getElementById('spinner').style.visibility = 'hidden'; md.innerHTML = page; //render markdown partial returned from the server }); mdText.value = ''; } miniSPA.changeUrl(); //initialize ``` 这两个对象对应的 html 片段如下： getEmoji.html : ```html

    GET request: Fetch emojis from Github pulic API.

    This is a list of emojis get from https://api.github.com/emojis:

    Get {{emojis.length}} items totally.

    • {{data.key}}
     ``` postMD.html : ```html

    POST request: send MD text and get rendered HTML

    markdown text here (for example: Hello world github/linguist#1 **cool**, and #1! ):

    Rendered elements from Github API (https://api.github.com/markdown):

    ``` ## 完整源代码 源代码在 [gh-pages](https://github.com/coderLMN/framework-free-single-page-app/tree/gh-pages) 分支里可以看到。 ## 演示地址 以上代码的在线演示可以在 [我的 Github 项目页面](https://coderlmn.github.io/framework-free-single-page-app/ ) 看到。 以上演示代码已经在 `Chrome`, `Firefox`, `Safari` 和 `Opera` 较新版本上测试过。`IE 9` 以上版本估计也可以，不过没测过。 另外，这些代码还有不少值得优化的地方，不过时间有限，主要是为了达到演示目的，让代码保持精简为好，所以暂时就不去改它了。 ## 前端技术探讨 我的[另外一个 repo](https://github.com/coderLMN/frontEndCourse) 里有我自己关于前端技术的一些思考和尝试。它对应的 [gh-pages](https://coderlmn.github.io/frontEndCourse/) 分支里有一些演示，还有几篇翻译文章，也欢迎讨论和指正。 ## 补充讨论 有同学提出了事件处理的问题，我更新了一下演示，说明如下： 事件的处理可以直接添加到元素上，不用改动现有代码。对于 data-repeat 元素，可以在事件响应方法的参数里传递它的 id 等唯一标识，例如在 ```html