Question

Here is playground: http://jsfiddle.net/n6W27/1/

try to Ctrl+A Ctrl+C Ctrl+V and see that contenteditable node was duplicated(at least for me in firefox).
The original question is how could I force only plain-text input into contenteditable block?
And the derived question is “Why the !@#$ node duplicated next to original one?”

Edit1: There is only one block in this demo, so I put caret inside editable block and then select all, copy, and paste

Edit2: result screenshot

Answer 1

If you can, change the element type to DIV. That will clear your issue.

<div class="edit" contenteditable>ABC</div>

If you don’t want your field to be block-level, set the display property to “inline-block”:

.edit {
    display: inline-block;
}

Live demo: http://jsfiddle.net/n6W27/2/