php while loop variable for every third div

Question

Is their a way in a while loop to assign a variable to a class in a div, for every third item in a while loop. I am using the blueprint structure and the third div is at the end and i need to attacht a "last" class name to every third div so 3rd div 6th div 9th div and so on?

/* LOOP THROUGH SHOEDATA TABLE */

$results = mysql_query("SELECT * FROM shoeData");


while($row = mysql_fetch_array($results)){

$name = $row['name'];
$about = $row['about'];
$company = $row['company'];
$buy = $row['buy'];
$tags = $row['tags'];
$id = $row['id'];
$image = $row['image'];


/* ECHO THE SHOEDATA RESULTS */     

    echo "<div class='imageBorder span-8 column'>";
        echo "<div id='imageHeight'>";
        echo "<img  src='thumbs/$image'>";
        echo "</div>";

        echo "<ul>";

            echo "<li>$name</l1>";
            echo "<li>$about</l1>";
            echo "<li>$company</l1>";
            echo "<li><a href='$buy'>BUY</a></l1>";
            echo "<li>$tags</l1>";
        echo "</ul>";
    echo "</div>";


}/*SHOEDATA WHILE LOOP ENDS */

Answer 1

for ($i = 0; $i < $numRecords; $i++)
{
 $className = "";
 if (($i % 3) == 0)
 {
  $className = "last"
 }

 ....
}

The key part here is the ($i % 3) == 0.

EDIT: The following is in response to your comment.

/* LOOP THROUGH SHOEDATA TABLE */

$results = mysql_query("SELECT * FROM shoeData");

$i = 0;
while($row = mysql_fetch_array($results)){
$i++;
$name = $row['name'];
$about = $row['about'];
$company = $row['company'];
$buy = $row['buy'];
$tags = $row['tags'];
$id = $row['id'];
$image = $row['image'];


/* ECHO THE SHOEDATA RESULTS */         
    $additionalClass = ($i % 3) == 0 ? " last" : "";
    echo "<div class='imageBorder span-8 column" . $additionalClass . "'>";
        echo "<div id='imageHeight'>";
        echo "<img  src='thumbs/$image'>";
        echo "</div>";

        echo "<ul>";

                echo "<li>$name</l1>";
                echo "<li>$about</l1>";
                echo "<li>$company</l1>";
                echo "<li><a href='$buy'>BUY</a></l1>";
                echo "<li>$tags</l1>";
        echo "</ul>";
    echo "</div>";


}/*SHOEDATA WHILE LOOP ENDS */

Answer 2

If you want to do this on the client-side it can be done with CSS3 (add JS for older browsers [DOMAssistant + Selectivizr]).

CSS: div.imageBorder:nth-child(3n) { /* style attributes will be applied to every 3rd div */ }

Answer 3

If the intention is to do something every X item use modulo. Modulo is the remainder of the division and becomes zero if the division is exact an integer.

if(!($counter%3)) {
    // this is 3 6 9 etc.
}
$counter++;

Of course you can do it with any number.