What tasks are achieved using PHP tag templates_PHP Tutorial

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1. The origin of templates

Before there was template technology, PHP was used to develop programs, usually It's all php code and html mixed together. For example, the news list is probably a newslist.php page with the following structure:

1. < ?
2. //Read the news records to be displayed from the database
3. ? >
4. < html> 
5. < head>…….. 
6. < /head>
7. < body> 
8. < ?
9. While ($news = mysql
   _fetch_array($result)) {
10. ?>
11. < !--Output news title -- >                                                           > ?
12. } ?> >
13. <
14. /body>
15. < /html>
16. So what’s the problem with this? First, it is not conducive to division of labor and cooperation. Generally speaking, programmers write the code and artists design the pages. In this method, the programmer must wait for the artist to design the interface before starting work. In other words, the work of programmers and artists cannot be synchronized. Secondly, it is not conducive to maintenance and has poor maintainability. For example, if you want to modify the interface after the program is fixed, the artist must modify it and then the programmer can add it again. Finally, the program structure is confusing and readable. HTML and PHP are mixed together, and once there are too many programs, it will become very messy. Understand the principles of templates - use PHP tag templatesTemplate technology emerged precisely to solve these problems. In order to solve these problems, the first thing that appeared was the use of PHP Label template. First of all, we need to understand what the purpose of templates is. How many tasks does the template mainly perform? First, the separation of art and programming. More precisely, it is the separation of obtaining data and displaying data. Second, division of labor. Good division of labor and cooperation.
For example, if you use the news list, if you use PHP tag template, we can divide the operation of the news list into two parts:

1. getnews.php is responsible for reading data from the database into the array $ In news, we don't care how $news is displayed.

Okay, in this way, we have achieved the separation of artists and programs and achieved our initial goal. But how to combine these two pages and realize the functions of listnews.php?

Suppose the code of getnews.php is as follows:

<ol class="dp-xml">
<li class="alt"><span><span class="tag"><</span><span> ?   </span></span></li><li><span>$</span><span class="attribute">news</span><span> =&ldquo;新闻列表&rdquo;;</span></li><li><span>//实际中应该是从数据库中读取出来的。   </span></li><li class="alt"><span class="tag">?></span><span>   </span></span></li>
<li><span>Shownesw.php的代码如下：   </span></li>
<li class="alt">
<span class="tag"><</span><span> </span><span class="tag-name">html</span><span class="tag">></span><span>   </span>
</li>
<li>
<span class="tag"><</span><span> </span><span class="tag-name">head</span><span class="tag">></span><span>   </span>
</li>
<li class="alt">
<span class="tag"><</span><span> </span><span class="tag-name">title</span><span class="tag">></span><span>显示新闻</span><span class="tag"><</span><span> /title</span><span class="tag">></span><span>   </span>
</li>
<li>
<span class="tag"><</span><span> /head</span><span class="tag">></span><span>   </span>
</li>
<li class="alt">
<span class="tag"><</span><span> </span><span class="tag-name">body</span><span class="tag">></span><span>   </span>
</li>
<li>
<span class="tag"><</span><span> ?=$news</span><span class="tag">?></span><span>   </span>
</li>
<li class="alt">
<span class="tag"><</span><span> /body</span><span class="tag">></span><span>   </span>
</li>
<li>
<span class="tag"><</span><span> /html</span><span class="tag">></span><span>   </span>
</li>
</ol>

Then, the code of this joint page listnews.php is very simple

<ol class="dp-xml"><li class="alt"><span><span class="tag"><</span><span> ?   </span></span></li><li><span>Include(&lsquo;getnews.php');</span></li><li><span>//获取数据   </span></li><li class="alt"><span>Include(&lsquo;shownesw.php');</span></li><li class="alt"><span>//显示数据   </span></li><li><span class="tag">?></span><span>   </span></span></li></ol>

Summary

Using the PHP tag template system can achieve a good separation of artists and programs, and at the same time facilitate the division of labor and cooperation between programmers and artists. For example, in the above example, shownews.php is created by artists. Maintenance, getnews.php is maintained by programmers. And listnews.php can be maintained by system designers. Of course, some agreed documents need to be added.

In fact, this simple example also illustrates the most basic MVC model. Among them, M, model, is responsible for reading data, which is equivalent to our getnews.php. V is the view, used to display data, which corresponds to shownews.php. Finally, there is controller C, corresponding to our listnews.php