能否通过按下退格键来防止删除span元素?
示例:http://jsfiddle.net/pvj64px9/1/
<div class="form-control" contenteditable="true">
<span class="correct-answer">
<span contenteditable="false">The correct answer is (A) 1 to 2. </span>
<span class="sentence" num="11">dgsdgsg. sgsdgs sgsgs.</span>
</span>
</div>
The correct answer is (B) 2 to 3. and `Choice A (1 to 2) is incorrect. ` must not be deleted.
正确答案是(B)2到3。
和选择A(1到2)是不正确的。
请勿删除。 - R-J