Having trouble nesting with three levels of quotes in PHP - php

Question

Please forgive me if I've posted this incorrectly, or there's an answer to this question somewhere - I have been searching for an answer to this but I haven't found one.
I'm nesting quotes within an echo statement and it's giving me grief (a 500 Error)
This code works (and various arrangements of double and single quotes):
<form action='update.php' method='post'>
<p>
<input type='hidden' name='log_id' value='<?php echo $row["log_id"]; ?>'/>
<input type='time' name='time_back' id='time_back'>
<input type='submit' value='Update'>
</p>
</form>
This code does not seem to work:
<?php
if($row["time_back"] == '00:00:00')
{ echo "<form action='update.php' method='post'>
<p>
<input type='hidden' name='log_id' value='<?php echo $row[\"log_id\"]; ?>'/>
<input type='time' name='time_back' id='time_back'>
<input type='submit' value='Update'>
</p>
</form>";}
else { echo $row["time_back"]; }
?>
I just can't quite see what I'm getting wrong here. I've poured over all sorts of stuff on nested quotes and I still can't figure it out.

Answer 1

The best thing to do (if you're not going to use a templating engine) is stop printing so much html with echo. I.e. close and reopen the PHP tag to make most of the HTML printed normally by being outside of PHP tags:
<?php
if($row["time_back"] == '00:00:00')
{
?>
<form action='update.php' method='post'>
<p>
<input type='hidden' name='log_id' value='<?php echo $row['log_id']; ?>' />
<input type='time' name='time_back' id='time_back'>
<input type='submit' value='Update'>
</p>
</form>
<?php
}
else { echo $row["time_back"]; }
?>
Second best, Close the quotes and concatenate, then reopen them:
<?php
if($row["time_back"] == '00:00:00')
{ echo "<form action='update.php' method='post'>
<p>
<input type='hidden' name='log_id' value='" . $row['log_id'] . "' />
<input type='time' name='time_back' id='time_back'>
<input type='submit' value='Update'>
</p>
</form>";
}
else { echo $row["time_back"]; }
?>

Answer 2

In your desired format
<?php
if($row["time_back"] == '00:00:00')
{ echo "<form action='update.php' method='post'>
<p>
<input type='hidden' name='log_id' value='<?php echo $row[\"log_id\"]; ?>'/>
<input type='time' name='time_back' id='time_back'>
<input type='submit' value='Update'>
</p>
</form>";}
else { echo $row["time_back"]; }
?>
You have a nested PHP statement - you're still working within the one you declared at the start, and are actually inside an 'echo' function that has not finished. There are many ways of merging your HTML with PHP, but one of the most readable
is the concatenation operator ..
So, with this method, the correction would be that in this line
<input type='hidden' name='log_id' value='<?php echo $row[\"log_id\"]; ?>'/>
You would instead write
<input type='hidden' name='log_id' value='" . $row["log_id"] . "'/>
Notice that we close the opening quote ", concatenate, output our PHP (we don't need the PHP tag or echo because we're already in an echo function, we just need to concatenate the string we want to be merged into the HTML), then concatenate again and reopen the ".
Hope that helps!

Answer 3

As was mentioned in comments, don't open a new PHP tag (i.e. <?php). Instead, just end the string literal (i.e. terminate with ") and concatenate the value from the variable (i.e. the array element: $row['log_id']).
<?php
if($row["time_back"] == '00:00:00')
{ echo "<form action='update.php' method='post'>
<p>
<input type='hidden' name='log_id' value='". $row["log_id"] ."'/>
<input type='time' name='time_back' id='time_back'>
<input type='submit' value='Update'>
</p>
</form>";}
else { echo $row["time_back"]; }
See it demonstrated in this playground example.