<form method="get" action="Index.php">
        <fieldset>
            <label for="powerof">Fibonacci: </label>
            <input type="text" name="powerof" value="<?php echo $_GET['powerof']; ?>"/>
            <input type="submit" name='Go' value="Calculate" />
        </fieldset>
    </form>
    <?php
    $message = 'The fibonacci sequence is: <br />1<br />2<br />';
    $powerof = 0;
    $max = 5;
    $temp = $max;
    if (isset($_GET['powerof'])) {
        $powerof = $_GET['powerof'];
    }
    if ($powerof > 100) {
        $powerof = 100;
        $message = 'Sorry, your input was too high. I converted it to the maximum value of 100.<br />The fibonacci sequence is: <br />1<br />2<br />';
    }
    $i = 1;
    for ($i; $i < $powerof; $i++) {
        $max = $max * $temp;
    }
    $x = 1;
    $y = 2;
    $z = $x + $y;
    echo($message);
    while ($z < $max) {
        $z = $x + $y;
        echo($z . "<br />");
        $x = $y;
        $y = $z;
    }
    ?>
this is my code and the issue is that if when i enter 1 into the text box rather than it just showing the 1st number within the sequence it shows the first 4 so for 2 it displays 1 2 3 5 8 13 21 34 rather than just 1 2, any ides guys???
Your error is at this lines :
for ($i; $i < $powerof; $i++) {
    $max = $max * $temp;
}
After this loop, the $max var is equal to 5^$powerof, which is not what you want.
Just remove this part and it should work fine.
Also change your test from
while ($z < $max) {
to
while ($z <= $max) {
if you want to include the maximum value.
<label for="powerof">Fibonacci: </label>
<input type="text" name="powerof" value="<?php echo $_GET['powerof']; ?>"/>
<input type="submit" name='Go' value="Calculate" />
</fieldset>
</form>
<?php
$message = 'The fibonacci sequence is: <br />1<br />2<br />';
$powerof = 0;
$max = 10;
$temp = $max;
if (isset($_GET['powerof'])) {
    $powerof = $_GET['powerof'];
}
if ($powerof > 100) {
    $powerof = 100;
    $message = 'Sorry, your input was too high. I converted it to the maximum value of 100.<br />The fibonacci sequence is: <br />1<br />2<br />';
}
$x = 0;
$y = 1;
$z = 0;
$counter = 0;
while ($counter < $powerof) {
    if ($counter <= 1) {
        $z = 1;
    } else {
        $z = $x + $y;
    }
    echo($z."<br />"); 
    $x = $y;
    $y = $z;
    $counter++;
}
?>
this is the working version
来源:https://stackoverflow.com/questions/24043237/create-a-mechanism-to-pass-in-a-positive-integer-and-display-all-the-values-of-t