问题
It seems it allows you to edit the content of an element, but what is actually happening? What's the use of this property?
EDIT: see here
回答1:
This is usually used for rich text input. While regular form elements like <input type="text"/> don't provide real rich text editing options, elements with contentEditable set to true can.
Most rich text editors (e.g. FCK Editor) available for the web are built using an <iframe/> with contentEditable set to true.
回答2:
contentEditable=true for elements make them editable. You can write/edit text in those elements as if they are a textarea or a text field.
来源：https://stackoverflow.com/questions/1654938/whats-the-use-of-element-contenteditable-true-in-html