当元素在HTML中失去焦点时，请使用onblur属性执行脚本。您可以尝试运行以下代码来实现 onblur属性-
<!DOCTYPE html>
<html>
<body>
<p>Type text below!</p>
Country: <input type = "text" name = "myid" id = "myid" onblur = "display()">
<script>
function display() {
var str = document.getElementById("myid");
str.value = str.value.toUpperCase();
}
</script>
</body>
</html>