停止CKEditor删除div

I've installed CKEditor in the backend of my website. I've got the following problem when switching from code view to wysiwyg view. The code I'm inserting is like:

<div class="span4">
    <p>Some text here</p>
</div>

When I switch back to view mode CKEditor automatically removes the div surrounding the paragraph.

Can anyone please help me to remove this problem? I don't mind staying in code view but I do like working in the view mode for writing longer text.

Thanks in advance.

Instead of disabling the ACF feature, use config.extraAllowedContent:

editor.config.extraAllowedContent = 'div(span4)';

or

editor.config.extraAllowedContent = 'div(*)';

Like AlfonsoMl said, this has something to do with the Advanced Content Filter

For all support about this look here: http://docs.ckeditor.com/#!/guide/dev_advanced_content_filter

or put the following line in your config to disable the content filter. (It's better to configure it)

CKEDITOR.config.allowedContent = true;

var editor1=CKEDITOR.replace('editor1');
editor1.config.allowedContent = true;