How to return PHP within PHP - AJAX - php

Question

Beginner to PHP, so I am pretty sure this is a stupid question...but, was hoping someone can help me out.
I have a html/php form, which basically dynamically pulls in values from a DB for a dropdown.
//HTML/PHP (original page)
<div style="position: relative; float: left; width:236px; margin-right: 20px;">
<div id="variablebox" style="position: relative; float: left; width:215px; border: solid #0096D6; border-width: 1px; padding: 10px;">
<H2>Step 2: Select Variable Type</H2>
<form id="var" enctype="multipart/form-data">
<span style="float: left; margin-top:8px;">
<label class="fieldlabel"><span>Variable Type:</span></label></br>
<select id="variabletype" name="variabletype" class="selectfieldshadow">
<option value="">Select</option>
<?php
$list=mysqli_query($con, 'SELECT * FROM valuelist');
while($row_list=mysqli_fetch_array($list)){
?>
<option value="<?php echo $row_list['valuelistid']; ?>">
<?php echo $row_list['valuename']; ?>
</option>
<?php
}
?>
</select>
</span>
When this form is submitted, it basically submits to PHP file via AJAX and then return the same form to the screen within the same DIV.
//PHP Page
echo "<H2>Step 2: Select Variable Type</H2>";
echo "<form id='var' enctype='multipart/form-data'>";
echo "<span style='float: left; margin-top:8px;'>";
echo "<label class='fieldlabel'><span>Variable Type:</span></label></br>";
echo "<select id='variabletype' name='variabletype' class='selectfieldshadow'>";
echo "<option value=''>Select</option>";
echo "<?php";
echo "$list=mysqli_query($con, 'SELECT * FROM valuelist');";
echo "while($row_list=mysqli_fetch_array($list)){";
echo "?>";
echo "<option value="<?php echo $row_list['valuelistid']; ?>">";
echo "<?php echo $row_list['valuename']; ?>";
echo "</select>";
echo "</span>";
echo "<span style='position: relative; float: left; display: inline-block; margin-top: 7px; font: 12px Lucida Grande,Helvetica,Arial,Verdana,sans-serif; padding-right: 60px;'>";
echo "<p>Add Value Control Screenshot:</p>";
echo "<input id='controlimage' type='file' name='controlimage'>";
echo "</span>";
I keep getting errors with my output...T_Variable this and Exception that...my question is, am I going about doing this correctly? I mean, looking at my PHP file that will return content back to the original page, do I have to echo php tags so they work on the original page when returned? ie. echo "<?php" etc..
Any assistance would be much appreciated!

Answer 1

echo is used to output content. As it's currently written, you're just trying to display the PHP code. To execute it, you'll have to restructure your code as follows:
<!-- some HTML code -->
<?php
// display stuff
?>
<!-- continue with HTML -->

Answer 2

Well first of all, PHP is all rendered server-side. So that means returning PHP in an AJAX response doesn't make sense. It won't render on the client side.
Second of all, those echos look crazy too. There are several different ways to output large text like that. Personally, I like to just close the PHP tag and write it. So your second file could look like this instead:
// end all PHP for now
?>
<H2>Step 2: Select Variable Type</H2>
<form id='var' enctype='multipart/form-data'>
<span style='float: left; margin-top:8px;'>
...
<input id='controlimage' type='file' name='controlimage'>
</span>
<?php
// continue writing PHP here

Answer 3

Send PHP is a nonsens cause PHP is a Server side language (run on server and not on the client, the browser).
Why don't you run your PHP code in this script and return the result. (Just display it)
But, please, make us proud of our favorite language and its beginners:
Use mysqli_fetch_assoc() instead of mysqli_fetch_array()
Use only one echo to do a multiline display, PHP natively supports it.
Indent your code, you will really like how it's more readable.
Use jQuery, its AJAX methods and autocomplete widget. Somebody did the job for you. ;-)