parameters - Remove unwanted paragraphs from string using php -

how remove unwanted

tags using pregmatch in below cases. wrote pregmatch not working cases. here string

<?php   $str='<div class="borderdummydiv" style="padding: 10px;"> <div class="showcolsec" style="line-height: normal;"> <p style="font-size: 14px;" data-mce-style="font-size: 14px;"><strong>email template testing - 01:</strong></p><p style="font-size: 14px;" data-mce-style="font-size: 14px;"><br data-mce-bogus="1"></p><p style="font-size: 14px;" data-mce-style="font-size: 14px;">email body testing autoresponder mails , email blasts scheduling functionality<br data-mce-bogus="1"></p> <p></p> <p><br></p> <p></br></p> <p>&nbsp; </br></p> <p>&nbsp; <br class="ddd"></p> <p class="ddd"></p> <p class="ddd"><br class="ddd"></p> <p class="ddd"></br></p> <p class="ddd">&nbsp; </br></p> <p class="ddd">&nbsp; <br class="ddd"></p> </div> </div>'; //echo $str;  echo preg_replace("/<p[^>]*>[\s|&nbsp;|<\br [^>]*>|<\/br>]*<\/p>/", '', $str);  ?> 

below unwanted paragraphs. how can remove string

<p></p> <p><br></p> <p></br></p> <p>&nbsp; </br></p> <p>&nbsp; <br class="ddd"></p> <p class="ddd"></p> <p class="ddd"><br class="ddd"></p> <p class="ddd"></br></p> <p class="ddd">&nbsp; </br></p> <p class="ddd">&nbsp; <br class="ddd"></p> 

in regexp in part <\br [^>]*> escape "b" backslash. make backspace. think don't want that.

try remove backslash makes it:

echo preg_replace("/<p[^>]*>[\s|&nbsp;|<br [^>]*>|<\/br>]*<\/p>/", '', $str); 

edit: (because of new information questioner) ok, 1 works:

echo preg_replace("/<p[^>]*>(\s|&nbsp;|<br [^>]*>|<\/?br>)*<\/p>/", '', $str); 

had replace square brackets round ones , make slash before "br" optional.