案例1:点击按钮禁用文本框
<input type="button" value="禁用文本框" id="btn" />
<input type="text" value="文本框" id="txt" />
<script>
document.getElementById("btn").onclick = function () {
document.getElementById("txt").disabled = true;
};
</script>
案例2:点击按钮修改列表的背景颜色
<input type="button" value="变色" id="btn" />
<ul id="uu">
<li>王陆</li>
<li>海云帆</li>
<li>闻宝</li>
<li>琉璃仙</li>
<li>王舞</li>
</ul>
<script>
document.getElementById("btn").onclick = function () {
document.getElementById("uu").style.backgroundColor = "pink";
};
</script>