$re = '/<(?:textarea|select).*?>.*?(\{\{\{variable:(.*?)\}\}\}).*?<\/(?:textarea|select)>|<(?:input).+?(value=.*?)(\{\{\{variable:(.+?)\}\}\})?.*?>|(\{\{\{variable:(.*?)\}\}\})/is';
$str = ' <section id="services">
<div class="container">
<div class="row">
<div class="col-md-12">
<p>You are using system version: {{{variable:system_version}}}</p>
<p>Your address: {{{variable:contact-email-address}}}</p>
<form action="http://k.loc/content/view/welcome" class="default-form" enctype="multipart/form-data" method="post" accept-charset="utf-8">
<input type="hidden" name="csrfkcmstoken" value="94ee71ada809b9a79d1b723c81020c78" />
<div class="row">
<div class="col-sm-12 form-error"></div>
</div>
<div class="row"><div class="col-sm-12"><fieldset id="personalinfo"><legend>Personal information</legend><div class="row"><div class="col-sm-12">
<div class="control-label">
<label for="testinput">Name<span class="form-validation-required"> * </span></label>
</div>
<div class="hint-text">Enter at least 2 characters and a maximum of 12 characters.</div><input id="testinput" name="testinput" placeholder="Enter your name here." class="input-group width-50" type="text" value="{{{variable:system_name}}} {{{variable:system_login}}}"><div class="row"><div class="col-sm-12"><div class="form-error"></div></div></div></div></div><div class="row"><div class="col-sm-12">
<div class="control-label">
<label for="testpassword">Password</label>
</div>
<div class="hint-text">Your password must be at least 12 characters long, contain 1 special character, 1 nunber, 1 lower case character and 1 upper case character.</div><input id="testpassword" name="testpassword" placeholder="Enter your password here." class="input-group width-50" type="password"><div class="row"><div class="col-sm-12"><div class="form-error"></div></div></div></div></div></fieldset></div></div><div class="row"><div class="col-sm-12"><fieldset id="bioinfo"><legend>Biographical information</legend><div class="row"><div class="col-sm-12">
<div class="control-label">
<label for="testtextarea">Biography</label>
<span class="hint-text">A minimum of 40 characters and a maximum of 255 is allowed. This hint is displayed inline.</span>
</div>
<textarea id="testtextarea" name="testtextarea" placeholder="Please enter your biography here." class="input-group-wide width-100" rows="5" cols="80">{{{variable:system_name}}}
{{{variable:system_login}}}</textarea><div class="row"><div class="col-sm-12"><div class="form-error"></div></div></div></div></div><div class="row"><div class="col-sm-12">
<div class="control-label">
<label for="testsummernote">Interests</label>
<span class="hint-text">A minimum of 40 characters is required. This hint is displayed inline.</span>
</div>
<textarea id="testsummernote" name="testsummernote" class="wysiwyg-editor" placeholder="Please enter your interests here."><p>{{{variable:system_name}}}<br></p><p>{{{variable:system_login}}}</p><p>{{{variable:activate_url}}}<br></p></textarea></div></div></fieldset></div></div><div class="row"><div class="col-sm-12"><button name="testsubmit" id="testsubmit" type="submit" class="btn primary">Submit<i class="zmdi zmdi-arrow-forward"></i></button></div></div>
</form> </div>
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php