代码示例:(标识:jsck_element_focus)
<!DOCTYPE html>
<html>
<body>

<h1>Element 对象</h1>

<h2>focus() 和 blur() 方法</h2>

<input type="text" id="myText" value="文本字段">

<p>单击按钮可在文本字段中赋予焦点或从文本字段中移除焦点。</p>

<button type="button" onclick="getFocus()">获得焦点</button>
<button type="button" onclick="loseFocus()">失去焦点</button>

<script>
function getFocus() {
  document.getElementById("myText").focus();
}

function loseFocus() {
  document.getElementById("myText").blur();
}
</script>

</body>
</html>
运行结果: