Computing

Call javascript from clicking a button, without submitting a form.

  
    <button type="button" class="mybuttonclass" onClick="jsfunction('arg')">Click to take non-submit action</button>

type="button" is not reduntant in this case. It is specifcally to allow a "button" tag to do something other than submit a form.

Inside a form, <button>xxx</button> (without the type="button") defaults to the "submit" action.

In or out of a form, <button type="button" onClick="jsfunction('arg')>xxx</button> performs the defined non-submit action.

Side note: the newer <button>xxx</button> can include images (and other things?), whereas the older <input type="button"> cannot.

Forms

  
    <form action="somepage.php" method="post">
    
        <input type="text" name="mytextfield" value="defaultvalue"><br>
        
        <input type="hidden" name="myhiddenfield" value="hiddenvalue">
        
        <select name="myselectfield">
        
        <option value="option1">Option 1</option>
        
        <option value="option2">Option 2</option>
        
        <option value="option3">Option 3</option>
        
        </select><br>
        
        <!-- Radio buttons with the same 'name' are mutually exclusive -->
        
        <input type="radio" name="myradiogroup" value="option1" checked>Option 1<br>
        
        <input type="radio" name="myradiogroup" value="option2">Option 2<br>
        
        <input type="radio" name="myradiogroup" value="option3">Option 3<br>
        
        <!-- A checkbox can be checked or unchecked independently -->
        
        <input type="checkbox" name="mycheckbox" value="checkvalue" checked>Check me!<br>
        
        <!-- Resetting the form returns all fields to their default values -->
        
        <input type="reset" value="Reset Form"><br>
        
        <!-- Submitting the form sends the named values to somepage.php -->
        
        <input type="submit" value="Submit Form">
        
    </form>

name="myname" is referenced in PHP with $_POST["myname"].

Submit a form with javascript

    <head>
    
        <script type="text/javascript">
        
            function submitMyForm() {
            
                document.getElementById('myform').submit();
            
            }
            
        </script>
    
    </head>
    
    <form id="myform" action="somepage.php" method="post">
    
        <input type="text" name="mytextfield" value="defaultvalue"><br>
        
        <input type="button" value="Submit Form" onClick="document.getElementById('myform').submit();">
        
    </form>

Pattern for using forms with PHP

 
    <?php
    
        if($_SERVER['REQUEST_METHOD'] == 'POST') {
        
            $myfieldvalue = $_POST['mytextfield'];
            
        }
        
    ?>
    
    <form action="thispage.php" method="post">
    
        <input type="text" name="mytextfield" value="metal rules"><br>
        
        <input type="submit" value="Submit Form">
        
    </form>

Returning associative array from a prepared statement

 
    $sql = "SELECT * FROM Valor.`Table` WHERE field1 = ? AND field2 = ?;";
    
    $stmt = $conn->prepare($sql);
    
    $stmt->bind_param("ss", $var1, $var2);
    
    $stmt->execute();
    
    $result = $stmt->get_result();
    
    $all_rows = $result->fetch_all(MYSQLI_ASSOC);
    
    foreach($all_rows as $row){
        
        $size  = $row['size']; 
        
        $alignment = $row['alignment'];;
        
    }
    
    $stmt->close();

PHP Recursive Folder Traversing

 
function getRecursiveFilenames($dirPath) {
    
    // Create a RecursiveDirectoryIterator
    
    $directoryIterator = new RecursiveDirectoryIterator($dirPath, RecursiveDirectoryIterator::SKIP_DOTS);
        
    // Flatten the directory structure into a single linear iterator
    
    $iteratorIterator = new RecursiveIteratorIterator($directoryIterator, RecursiveIteratorIterator::LEAVES_ONLY);
    
    $filenames = [];
    
    foreach ($iteratorIterator as $file) {
     
        // Use getPathname() to get the full path and filename
        
        $filenames[] = $file->getPathname();
        
        // Alternatively, use getFilename() for just the file name
        
        // $filenames[] = $file->getFilename();
        
        // Or use getRealPath() for the absolute path
        
        // $filenames[] = $file->getRealPath();
        
        // Or use SplFileInfo methods for other info
        
        // $filenames[] = $file->getBasename(); 
        
    }  
        
    return $filenames;
    
}

Get Files Matching a Pattern and loop through the lines of each file

 
$pattern = '/^.*.html$/';

$files = preg_grep($pattern, scandir("Creatures/SourceWebsites/aonprd"));

foreach ($files as $filename) {

$lines = file("Creatures/SourceWebsites/aonprd/$filename", FILE_IGNORE_NEW_LINES);

foreach ($lines as $line) {

$line = trim($line);

}

}

Pattern Matching

 
$pattern = '/.*>(.*)/';

$matches = [];

preg_match($pattern, $aln, $matches);  

$aln = $alignments[$matches[1]] ?? $matches[1];

The pattern captures everything after the first occurrence of ">".
$matches[0] contains the entire matched string, while $matches[1] contains the part captured by the parentheses, which is the text after ">".
The ?? operator is the null coalescing operator. It returns the value on its left if it exists and is not null; otherwise, it returns the value on its right. In this case, if $alignments[$matches[1]] is set and not null, it will be used; otherwise, $matches[1] will be used.
This is a common pattern for looking up a value in an associative array and providing a default if the key is not found.

Test string starts with substring

 
if (substr($string, 0, strlen($needle)) === $needle)
    
     - OR -
     
if (strpos($string, $needle) === 0)     
    
     - OR -
     
if (strncmp($string, $needle, strlen($needle)) === 0)
    
     - OR -
     
if (preg_match('#^' . $needle . '#', $string === 1))

Substring Substitution

 
function anchorfy($haystack){
    
       $needles = [" ", "-", ",", ":", "'", "\"", "(", ")", ".", "!", "?", "#", "$", "%", "&", "*", "+", "/", "\\", "|", "<", ">", "@", "^", "~"];
    
        $haystack = str_replace($needles, "", $haystack);
    
       return $haystack;
    
}

You can use a non-array value for a needle, of course. I decided to use the fanciest example I have so far had a need for.

Even fancier, you can use both a $needles array, and a $replacement array. If both arrays have the same count, then the value at postion X in the needles array will be replaced with the value at psoition X in the replacement array.

Convert html special characters to their html codes.

echo htmlspecialchars("Rock & Roll > alles") . PHP_EOL;

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