I was always curious, is there any significant advantage or disadvantage of writing php inside html or vice versa
example:
echo '<ul>'
foreach ($items as $item)
{
echo "<li>$item</li>";
}
echo '</ul>
As opposed to:
<ul>
<? foreach($items as $item): ?>
<li>$item</li>
<? endforeach; ?>
</ul>
Since these essentially generate the same thing, when would you actually use one over the other?
Functionally they are the exact same and won't have an appreciable affect on performance, if any. It comes down to personal preference and readability - if one is clearer than the other and will be easier for others (or the future you) to understand, go with that one.
I personally find it better to use the latter if you actually have PHP in a mostly HTML file. The clear opening/closing tags match up visually with HTML easier. I find it can be hard to line up curly braces visually.
As an example, in the case of a MVC framework I would use the first way of outputting things in a controller or model context, while the second way in my view files. Some templating languages like smarty have similar looking constructs.
ie:
{ if [condition] }
{ /if }
The first one echoes meaningless strings from the IDE's point of view, whereas the latter one is a mix of HTML and PHP and will be handled properly by your editor. In other words, it's better to actually separate HTML from PHP as it allows your editor to parse HTML and provide some usefull features like syntax validation or autoclosing of HTML tags.
basically php is a server side scripting and html is client side scripting. So if it is php inside html then it generates faster response and you can format a better view. However for some scenario you might have to consider the other case for developing.
Related
I'm rather new to programming and i know how to separate PHP from HTML, but i would like to know if there is any difference in doing
this:
<?php $rand="I love apples" ?>
<h1>This is a title</h1>
<div>
<p>This is a paragraph</p>
<?php echo"The variable contains the string $rand"; ?>
</div>
?>
compared to doing this:
<?php
echo "<h1>This is a title</h1>";
echo "<div>";
echo "<p>This is a paragraph</p>";
echo "The variable contains the string $rand";
echo "</div>";
?>
Is there any difference between in performance etc, between splitting the PHP code from the HTML code and just echoing the whole page in php?
The best practice is not to seperate PHP from HTML, the best practice is to seperate logic from markup.
Also important is coding style. Proper line indentions. Using echo "</div>"; instead of echo"</div>";, valid HTML, not putting variables into quotations:
echo "The variable contains the string $rand";
better (why? see my comment below):
echo "The variable contains the string ",
$rand,
" :-)";
Your whole project gains much quality and worthness just by improving the code, writing clean, readable, maintainable. Imagine you want to change the Text, you would have to add or change lots of echoes.
Code Style Guides > Pear,
PSR, Zend <
encourage developers to keep their code readable, valid and cross-browser compatible
The problem is not performance, it's about readability and more importantly, maintainability.
Doing all the processing in one place, and all of the output in another (i.e. Logic and Presentation), would mean you will have an easier time altering one without affecting the other too drastically.
To your specific question, the top method is preferable by far, for the reasons listed above.
Taking your question at face value, there are two reasons that come to mind immediately:
Assuming you're using a smart editor, echoing all your HTML will cause you to lose syntax highlighting for it, so you're less likely to catch errors.
Because everything is inside a PHP string, now you have to worry about escaping all your other special characters. Try spitting out some Javascript with a string in it and let us know how fun that is.
However, when most people say something like "separating PHP from HTML" they are referring to the concept of separating your logic from your views. It means don't put complex business logic, computations, and database calls inside your html pages. Keep that all in pure PHP files, and have your html files contain minimal PHP that's only used to spit out your data.
<?php $rand="I love apples" ?>
<h1>This is a title</h1>
<div>
<p>This is a paragraph</p>
<?php echo"The variable contains the string $rand"; ?>
</div>
?>
The above looks poorly separated. This is what php/html separation should look like:
<?php
$rand="I love apples";
?>
<h1>This is a title</h1>
<div>
<p>This is a paragraph</p>
<p>The variable contains the string <?=$rand ?></p>
</div>
Performance-wise, that's not an issue but it would do much favor for programmers to be able to read the code easily, hence the need for HTML/PHP separation practices. Ideally, if you're going to do just one script, keep all your PHP code at top. Also, other reason for the separation is that IDE editors can easily format HTML nicely. If there's a HTML tag inside the PHP tag that is ending with a HTML tag outside of PHP, then HTML cannot be formatted correctly. For example:
<div><p>And it offers so much <?php echo "$features</p>
<h2>Proven Ideas";?></h2>
<p>More details ahead</p>
</div>
The above will run just fine but the IDE html formatter will likely be confused with missing end tags and won't format making it more difficult for programmers to read them.
I think you example is not a good one that makes it very clear why you should separate it.
The reason why you should separate not just HTML but the presentation, rendering or UI part of your application is clean coding and separation of concerns. This will make sure your get clean, easy to read code and makes your application maintable.
Take Wordpress for example, it is an extremely fugly mix of php and HTML. They even do SQL queries in the presentation layer of the application, if you can even draw a borderline between presentation and other logic in this thing.
You'll always have to output some dynamic content in your HTML but really try to reduce it to echoing variables and having some output formatting helper objects there. All business logic should be somewhere else, just not in the "templates" or whatever else you'll call the files that contain the output.
Have a look at the MVC pattern for example, it gives you a good idea of how and why you want to separate things.
In my opinion, it depends on the level of HTML formatting that is being done versus PHP logic. Nothing more & nothing less. It’s simply easier to read pure HTML as pure HTML or PHP as straight PHP. When it is all jummbled together—the way some templating systems handle it—it becomes a logical headache to read & debug. So I err on the side of placing HTML in PHP for my own sanity’s sake.
Unclear on the performance pluses or minuses if there are any. But can assure you that in 20+ years I have never had a server slow down because of too much HTML embedded in PHP
Personally, I would format your code example like this:
<?php
echo "<h1>This is a title</h1>"
. "<div>"
. "<p>This is a paragraph</p>"
. "The variable contains the string $rand"
. "</div>"
;
?>
I like this method since there is one echo—which makes it clear what is happening—and the rest of the HTML is just concatenated via . characters.
Also, remember all formatting in programming benefits HUMANS more than anything. A computer only needs to see the commands, so if you want to be pitch perfect for a machine, just code without any spaces or formatting. Heck, stop using full words & just use 1 letter variables! Oh wait, that is how it was done in ye olden days.
Nowadays compilers & caching systems are designed to take human readable code & make it machine optimized.
Which is all to say: You should code towards readability & logic on your part. Nothing more & nothing less.
Is there an standard output library that "knows" that php outputs to html?
For instance:
var_dump - this should be wrapped in <pre> or maybe in a table if the variable is an array
a version of echo that adds a "<br/>\n" in the end
Somewhere in the middle of PHPcode I want to add an H3 title:
.
?><h3><?= $title ?></h3><?
Out of php and then back in. I'd rather write:
tag_wrap($title, 'h3');
or
h3($title);
Obviously I can write a library myself, but I would prefer to use a conventional way if there is one.
Edit
3 Might not be a good example - I don't get much for using alternative syntax and I could have made it shorter.
1 and 2 are useful for debugging and quick testing.
I doubt that anyone would murder me for using some high-level html emitting functions of my own making when it saves a lot of writing.
In regards to #1, try xdebug's var_dump override, if you control your server and can install PHP extensions. The remote debugger and performance tools provided by xdebug are great additions to your arsenal. If you're looking only for pure PHP code, consider Kint or dBug to supplement var_dump.
In regards to #2 and #3, you don't need to do this. Rather, you probably shouldn't do this.
PHP makes a fine HTML templating language. Trying to create functions to emit HTML is going to lead you down a horrible road of basically implementing the DOM in a horribly awkward and backwards way. Considering how horribly awkward the DOM already is, that'll be quite an accomplishment. The future maintainers of your code are going to want to murder you for it.
There is no shame in escaping out of PHP to emit large blocks of HTML. Escaping out to emit a single tag, though, is completely silly. Don't do that, and don't create functions that do that. There are better ways.
First, don't forget that print and echo aren't functions, they're built in to the language parser. Because they're special snowflakes, they can take a list without parens. This can make some awkward HTML construction far less awkward. For example:
echo '<select name="', htmlspecialchars($select_name), '</select>';
foreach($list as $key => $value) {
echo '<option value="',
htmlspecialchars($key),
'">',
htmlspecialchars($value),
'</option>'
}
echo '</select>';
Next, PHP supports heredocs, a method of creating a double-quoted string without the double-quotes:
$snippet = <<<HERE
<h1>$heading</h1>
<p>
<span class="aside">$aside_content</span>
$actual_content
</p>
HERE;
With these two tools in your arsenal, you may find yourself breaking out of PHP far less frequently.
While there is a case for helper functions (there are only so many ways you can build a <select>, for example), you want to use these carefully and create them to reduce copy and paste, not simply to create them. The people that will be taking care of the code you're writing five years from now will appreciate you for it.
You should use a php template engine and just separate the entire presentation and logic. It make no sense for a educated programmer to try to create a library like that.
My friend writes everything using phps echo.
I mean he starts <? and echo everything, including header, main part, footer, he even has style.php file where he echos some css and then includes it in main project.
question is why is it better to do that way ? Or is it better at all?
Cause in dreamveawer everything is red. I mean it understands evrything as phps srtings and makes all text red.
If you do not use echo you have different colors in code and you can see where is ccs, javascript or html.
So what's better to write normally or I should try the same "echo everything" practice ?
No, it is no better to do that way.
Do not use echo to output HTML but divide your code into 2 parts - business logic part and presentation logic part, a latter one consists of mostly HTML with PHP used only to output data coming from the business logic part
a little example of such a template:
<? if ($err): ?>
<? foreach($err as $e): ?>
<div class="err"><?=$e?></div>
<? endforeach ?>
<? endif ?>
<form>
<input type="text" name="name" value="<?=$form['name']?>">
<textarea name="comments"><?=$form['comments']?></textarea>
<input type="submit">
</form>
If that's how he does it, then please slap him across the back of the head for us please?
But seriously, there is this thing called MVC, please take a look at it, comprehend it, implement it and explain it to your friend.
That's horrendous.
You should try not to mix PHP and HTML if you can help it.
In some cases you will be interleaving some dynamic content with static content (and you could use a templating engine for that); but outputting the entire HTML document via PHP statements is a clear sign of insanity and sadism.
You might be interested in templates. They're not html nor php, but a combination between these two.
The advantage is that you can see/edit/update/maintain your code much easier, because the actual php part is somewhat separated from the html markup.
The main disadvantage is that it might be a bit slower, since php reads the template, makes replacements and then spits out the html.
Here's a link to some of the most used php template engines.
Using HTML code instead of echoing has the advantage that the editor (Dreamweaver in your case) can do syntax highlighting. This will help you find errors in your HTML faster.
Also, you don't have to think too much about escaping quotes in your HTML (you still need to think about proper escaping your PHP variables anyway).
I can think of several ways the bad habit of echoing everything can be formed:
Errors from missing PHP tags while intermingling PHP and HTML. For a newbie it takes a while to wrap your head around the concept of using one language (PHP) to write code in another language (HTML). I remember when I first learned PHP I thought it would be easier to echo everything instead of opening and closing PHP tags all the time.
Coming from a language background where every output must be printed explicitly.
Having read some insane micro-optimization article on the web that claims echoing is faster or more secure.
For the most part, when I want to display some HTML code to be actually rendered I would use a 'close PHP' tag, write the HTML, then open the PHP again. eg
<?php
// some php code
?>
<p>HTML that I want displayed</p>
<?php
// more php code
?>
But I have seen lots of people who would just use echo instead, so they would have done the above something like
<?php
// some php code
echo("<p>HTML that I want displayed</p>");
// more php code
?>
Is their any performance hit for dropping out and back in like that? I would assume not as the PHP engine would have to process the entire file either way.
What about when you use the echo function in the way that dose not look like a function, eg
echo "<p>HTML that I want displayed</p>"
I would hope that this is purely a matter of taste, but I would like to know if I was missing out on something. I personally find the first way preferable (dropping out of PHP then back in) as it helps draw a clear distinction between PHP and HTML and also lets you make use of code highlighting and hinting for your HTML, which is always handy.
The first type is preferable, exactly for the reasons you mentioned.
Actually, echoing out whole chunks of html is considered bad practice.
No, there's no performance increase that would be visible.
Sometimes its just simply easier to output content using echo (for example, when inside a while or for loop) than to close the php tag.
I think there's a preprocessor which converts the same form into the second. That's what happens in ASP.NET, anyway. And in both ASP.NET and classic ASP, loops can actually stretch across raw-HTML regions.
There's no performance difference at all.
Just the style that produces the most readable code. Depending on the actual situation that can be either of the two.
But mixing HTML and PHP should be avoided where possible anyway. THis can be accomplished by using a template system for your views.
So I've always developed PHP pages like this: <?php goes at the top, ?> goes at the bottom, and all the HTML gets either print()ed or echo()ed out. Is that slower than having non-dynamic html outputted outside of <?php ?> tags? I can't seem to find any info about this.
Thanks!
--Mala
UPDATE: the consesus seems to be on doing it my old way being hard to read. This is not the case if you break your strings up line by line as in:
print("\n".
"first line goes here\n".
"second line goes here\n".
"third line");
etc. It actually makes it a lot easier to read than having html outside of php structures, as this way everything is properly indented. That being said, it involves a lot of string concatenation.
I'm not sure about speed, but it's typically best practice to separate dynamic elements and the display of them.
Check out a framework like CodeIgniter: This has a "controller" and a "model" that grab data, sort it or do whatever you like with it, and then feed it to a "view" (some sort of template).
This paradigm is called MVC, and is a really, really valuable thing to learn about. I've found its chief advantage to be easier-to-maintain code. I don't end up with a monster document that I have to re-learn each time I approach it.
Resources:
CodeIgniter
MVC
The difference in speed is probably negligible, however, when **print()**ing out all of your HTML with PHP, the code can get very ugly, and makes it much harder to read than if you just have plain HTML.
Edit: Also, if you're are **print()**ing out static HTML that doesn't change, really what is the point? It gives you no added benefit.
Pros
None that I can see
Cons
Code that is hard to read
One more step in processing for the PHP engine, which although probably not noticeable, it is an extra step.
The speed is negligible - trust me, this will not be your bottleneck.
Along with any other MVC framework, you might want to check out a simple templating system, such as Smarty, which separates your PHP logic from your HTML and also does caching.
I don't know if it's slower or faster, but (in my opinion) it makes the code a lot more difficult to understand. Which I guess is why I don't typically do it.
It is almost the same from a performance point of view.
I would set the focus on the readability of the code. If you have a performance problem, figure out the bottleneck and cache it.
Is that slower than having non-dynamic html outputted outside of <?php ?> tags?
Well yes, it is... marginally. But that's not really the issue: it's all about the readability.
this way everything is properly indented
Your example isn't indented at all, which is fairly typical for the print-heavy, PHP I've unfortunately had to maintain!
Try this approach to keeping good, consistent indentation:
<ul>
<?php
// block of arbitrary code blah blah
//
$conditions= get_conditions_from_request();
$isadmin= $user->privileges>=PRIV_ADMIN;
?>
<?php foreach (select_things($conditions) as $thing) { ?>
<li>
<strong><?php h($thing->title); ?></strong>
<?php if ($isadmin) { ?>
<a href="/editthing.php?id=<?php u($thing->id); ?> (Edit) </a>
<?php } ?>
<?php h($thing->description); ?>
</li>
<?php } ?>
</ul>
(This presumes a function h that calls echo htmlspecialchars and u that does echo htmlspecialchars urlencode. Getting this escaping stuff right is essential to having a secure site, and is something that's almost always wrong in print-based PHP, as it tends to use "blah $var blah"-style templating without any escaping at all.)
Maybe not the best practice, but I choose to mix and match print() statements. For large chunks of layout code, I don't use print(), but if I'm rendering a complex if/else or for/while block and I'd be exiting the PHP block every other word, then I'll print out the non-dynamic text with the dynamic text.
Performance is very negligible at best. You can create a page, and put a timer on it. (Here is a tutorial on creating a script timer)
Output the exact same data both ways, and measure it with as many samplings as you can get, this should roughly tell you which is faster. I'm guessing very close to the same.
I have seen a lot of these pages with PHP embedded inside HTML, and I don't like it. As Alex Mcp suggested you should be thinking about a MVC model.
The problem with scripts embedded into html is the flow control and logic aren't easy to read, and there are some wierd problems that occur here and there. The best solution for me is usually to use Smarty or the Zend Framework to create template pages and then swap the data that goes in and out. Much easier to manage in the long run.