​x
 
<!DOCTYPE html>
<html>
<body>
​
​
<p>当您点击input控件时，会触发一个将背景颜色设置为黄色的函数。当您离开输入字段时，会触发一个删除背景颜色的函数。</p>
​
<input type="text" id="fname" onfocusin="focusFunction()" onfocusout="blurFunction()">
​
<script>
function focusFunction() {
  document.getElementById("fname").style.backgroundColor = "yellow";
}
function blurFunction() {
  document.getElementById("fname").style.backgroundColor = "";
}
</script>
​
</body>
</html>
​