Conventions for combining PHP with HTML - php

Question

I am studying PHP from a book. The author uses echo to output HTML. At first I thought that this was how it supposed to be done, but then I picked up a more "advanced" book. The author of the second book inserted PHP code between HTML rather then echo the whole thing. How is it done in large web development companies that work on large projects? Can you use either, or is one more accepted than the other?
Take this code for example:
<?php
//pagination
if ($pages > 1) {
//determine the current page
$current_page = ($start / $display) + 1;
//print out Previous Page button
if ($current_page != 1) {
?>
<div class="pages"><strong> < </strong></div>
<?php
}
//print the page numbers
for ($i = 1; $i <= $pages; $i++) {
if ($i == $current_page) {
?>
<div class="pages active"><span> <?php echo $i; ?> </span></div>
<?php
}
else {
?>
<div class="pages"><strong> <?php echo $i; ?> </strong></div>
<?php
}//end of $i = $current_page conditional
}//end of FOR loop
if ($current_page < $pages) {
?>
<div class="pages"><strong> > </strong></div>
<?php
}
}//end of pagination
include('includes/footer.php');
?>
Is that the correct way of doing it, or should I use something like this:
echo '<a href="view_users.php?s=' . ($display * ($i - 1)) .
'&p=' . $pages . '&sort=' . $sort . '">' . $i . '</a> ';
The reason why I'm asking is because I find it difficult to properly align the HTML when using the second technique, and I don't want to develop any bad habits early on.

Answer 1

The first method makes your code more readable. The second method is useful when you need to print some little amount of html code. Also you can use short open tags to insert your php code between html tags. For example if you need to print language parameter of URL you can do like this:
<a href="index.php?lang=<?=$lang?>" >A Link</a>
This is equal to this:
<a href="index.php?lang=<?php echo $lang; ?>" >A Link</a>

Answer 2

I'd recommend using a good framework in general, and a templating engine for outputting pages. This way, your data models, your application logic, and your HTML are all kept separate.

Answer 3

This is a somewhat subjective question, but:
echo '<a href="view_users.php?s=' . ($display * ($i - 1)) .
'&p=' . $pages . '&sort=' . $sort . '">' . $i . '</a> ';
This is not very good, because it quickly becomes hard to read. It's the worst option to use IMO.
Here an evolution on how this can be improved:
<a
href="view_users.php?s=<?php echo $display * ($i - 1); ?>&p=<?php echo $pages; ?>&sort=<?php echo $sort; ?>">
<?php echo $i; ?>
</a>
<?php
printf('%i',
$display * ($i - 1), $pages, $sort, $i);
?>
<?php
$q = http_build_query(array(
's' => $display * ($i - 1),
'p' => $pages,
'sort' => $sort
));
?>
<?php echo $i; ?>
<?php
printf('%i',
http_build_query(array(
's' => $display * ($i - 1),
'p' => $pages,
'sort' => $sort
)),
$i);
?>

Answer 4

Paul, what you're looking at in that code is a combination of PHP, CSS and HTML. echo just means print on page and it is a PHP function which is why you see it with the tags.
<?php ?>
Does this answer your question?
Also PHP and HTML and CSS will not parse any whitespace so indenting is done to enhance readability. I suggest you comment your code and format it however it is easier for you to understand. From a professional standpoint check out the W3C validator for proper code formatting.

Answer 5

Both are acceptable really, using echo for short statements and completely breaking out of php for long bits of html. Indentation of your HTML doesn't matter that much, it just looks pretty when someone checks out your source.

Answer 6

wrapping html generation in functions and building output strings can be a good practice. That way you can have complex logic expressed in a readable way:
<?php
function get_pagination_html($pages, $start, $display) {
$html = "";
if ($pages <= 1) return $html;
$current_page = ($start / $display) + 1;
if ($current_page != 1) {
$previous = $start - $display;
$html .= "<div class='pages'><strong><a href='view_users.php?s={$previous}&p={$pages}'> < </a></strong></div>";
}
for ($page_number = 1; $page_number <= $pages; $page_number++) {
if ($page_number == $current_page) {
$html .= "<div class='pages active'><span> {$page_number} </span></div>";
} else {
$page_start = $display * ($page_number - 1);
$html .= "<div class='pages'><strong><a href='iew_users.php?s={$page_start}>&p={$pages}'> {$page_number} </a></strong></div>";
}
}
if ($current_page < $pages) {
$next = $start + $display;
$html .= "<div class='pages'><strong><a href='view_users.php?s={$next}&p={$pages}'> > </a></strong></div>";
}
return $html;
}
echo get_pagination_html($pages, $start, $display);
Notice how much easier it reads. You also don't need any comments because variable names are self explanatory