Gateway is down because of PHP code in one situation - php

Question

Here is the code (HTML / PHP) :
<div class="col-sm-6">
<div class="form-group">
<select id="horseSize" name="horseSize" class="form-control" >
<option value="<?php echo htmlspecialchars($horseSize); ?>" selected><?php echo htmlspecialchars($horseSize); ?> m</option>
<?php
$i = 0.50;
while($i <= 2.00){
if ($i != $horseSize){
?>
<option value="<?php echo htmlspecialchars(number_format($i, 2)) ; ?>"><?php echo htmlspecialchars(number_format($i, 2)) ; ?> m</option>
<?php
$i = $i + 0.01;
}
}
?>
</select>
</div>
</div>
$horseSize comes from a SQL query and is working fine. Th problem is in displaying webpage.
When i am trying to display this webpage, my website goes down because of gateway giving no answer. This triggers only in one situation : if the variable value of $horseSize is inferior to 1. As if it was not possible to display something like 0,....
Maybe I did something wrong in this code, but I tried many times to fix, I couldn't reach it.

Answer 1

you are incrementing $i only under if condition, so value like 0.50 it will always never increase. Also floating point comparison will not work. please read: Floating point numbers
<div class="col-sm-6">
<div class="form-group">
<select id="horseSize" name="horseSize" class="form-control" >
<option value="<?php echo htmlspecialchars($horseSize); ?>" selected><?php echo htmlspecialchars($horseSize); ?> m</option>
<?php
$i = 0.50;
$precision = 0.00001;
while($i <= 2.00){
if(abs($i-$horseSize) > $precision) {
?>
<option value="<?php echo htmlspecialchars(number_format($i, 2)) ; ?>"><?php echo htmlspecialchars(number_format($i, 2)) ; ?> m</option>
<?php
$i = $i + 0.01;
} else {
$i = $i + 0.01;
}
}
?>
</select>
</div>
</div>