如何使用正则表达式形成此替换

I need to remove a particular string using php, the string needs to start with <div class='event'> followed by any possible string but which contains $myVariable, which is then followed by </div>. How do I remove all this using preg_replace()? I have worked out it might be something like this

preg_replace("<div class='event'>(.*)" . $myVariable . "(.*)</div>", "", $content);

But I cant get it to work.

Update:

I need to remove a div and everything inside it, the div contains an event name and date but I can only delete the div based on the events name and so the date needs to be defined as practically any string.

Let's imagine you have a <div> and inside it, there is some text node with a specific word you define with $myVariable.

The task is:

  1. Read the document in
  2. Initialize DOM
  3. Collect the <div> tags with .nodeValue containing $myVariable text
  4. Remove those tags from the DOM
  5. Return updated DOM

The code for that algorithm is below (DOM is initialized with a HTML string in the demo):

$html = "<<YOUR_HTML_STRING>>"
$dom = new DOMDocument;               // Declaring the DOM
$dom->loadHTML($html);                // Initializing the DOM with an HTML string
$myVariable = "2015-09-12";           // Your dynamic variable

$xpath = new DOMXPath($dom);          // Initializing the DOMXpath
$divs = $xpath->query("//div[contains(.,'$myVariable')]"); // Collecting DIVs 
                                                           // having $myVariable
foreach($divs as $div) { 
   $div->parentNode->removeChild($div); // Removing the DIVs
}

echo $dom->saveHTML();                  //  Getting the updated DOM

See IDEONE demo

Note that you can force DOMDocument to omit adding !DOCTYPE using the following to declare and initialize DOM:

$dom = new DOMDocument('1.0', 'UTF-8');
$dom->loadHTML($html, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);