text-align属性只能在内联元素
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
.box {
padding: 10px;
background-color: #cd0000;
text-align: center;
width: 500px
}
.content {
display: inline-block;
text-align: left;
}
</style>
</head>
<body>
<div class="box">
<p id="conMore" class="content">文字内容</p>
</div>
<!-- 按钮 -->
<p><button id="btnMore">更多文字</button></p>
<script>
var btn = document.getElementById('btnMore'),
content = document.getElementById('conMore');
if (btn && content) {
btn.onclick = function() {
content.innerHTML += '-新增文字';
};
}
</script>
</body>
</html>
集合、和深浅拷贝)
