html - Php Checkbox Checked struggling -

ok don't know i'm doing wrong, i'm trying modify css when checkbox crossed.

here html code:

<input type='submit' name='com' value="ajouter commentaire" /> <input type="checkbox" name="checkboxh"> 

php:

if( isset($_post['com']) && isset($_post['checkboxh']) ) { echo '<style type="text/css">     #com {         display: none;     }     </style>'; } else { //do smth else } 

after checking checkbox , pushing submit, div still visible.

you need add id="com" attribute div.