div模拟textarea以实现高度自适应实例页面

CSS代码：

.test_box {
     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;
    -webkit-user-modify: read-write-plaintext-only;
}

HTML代码：

<div class="test_box" contenteditable="true"><br /></div>

JS代码：

if (typeof document.webkitHidden == "undefined") {
    // 非chrome浏览器阻止粘贴
    box.onpaste = function() {
        return false;
    }
}