How would I write this split with php instead of javascript
<p>I was manipulating a string with javascript to split numbers that i need in a pattern like this :</p>

<pre><code>150952-0535 
</code></pre>

<p>generated from a number like this :</p>

<pre><code>15095205350008
</code></pre>

<p>The javascript is like this and it does the trick :</p>

<pre><code>var s7img = '15095205350008';
s7img = '&lt;img src="http://site.com/images/' 
          + s7img.substring(0, 6) + "-0" 
          + s7img.substring(7, s7img.length - 4)
          + '?$product_stamp$"&gt;';
</code></pre>

<p>How could I accomplish the same thing just using php?  I started poking around with something like :</p>

<pre><code>$sku = "15095205350008";
$s7img = substr($sku, 0,6); 
</code></pre>

<p>But I am not sure... </p>
