div模拟textarea

核心属性contenteditable=true！

.text_box{         width: 400px;               min-height: 120px;               max-height: 300px;              _height: 120px;               margin-left: auto;               margin-right: auto;               padding: 3px;               outline: 0;               border: 1px solid #a0b3d6;               font-size: 12px;               word-wrap: break-word;              overflow-x: hidden;              overflow-y: auto;      }<div contenteditable='true' class='text_box'><br/></div>