By default, WordPress strips out textareas in your posts. This is designed with security in mind but it can nonetheless be frustrating especially when you post a lot of code like me – where I like to give out code snippets for my readers. It’s also bad for affiliate managers who use WordPress.
I’ve noticed on certain installations, the textarea will disappear from your post. When you view the post in the admin area, you’ll see the code ‘greyed out’ in a band and you can’t get to it. If you need to put code anywhere in your post or Pages, the better way would be to use a syntax highlighter plugin. This will take you to a list of syntax highlighter plugins you can use.