i bir html formu var

<form action="" method="post">
<textarea id="content" name="content"></textarea >
</form>

ok it work good when making var_dump($_post); but the problem is when adding any js plugin on this textarea its not give me any out put this in my new script i cant know the reason i testes many plugins like text area resize like nic editor like ckeditor and many things every thing is ok and i can not know the reason the problem is every thing is ok and there is a problem its give me empty if i write any thing in the textarea