Prototype - Form focusFirstElement() 方法
此方法将键盘焦点放在表单的第一个元素上。
通过将页面加载时的焦点放在用户可立即开始输入的搜索表单或联系表单等表单上，此方法有助于增强网站的可用性。
语法
form.focusFirstElement();
返回值
它返回 HTMLFormElement。
示例
<html>
<head>
<title>Prototype examples</title>
<script type = "text/javascript" src = "/javascript/prototype.js"></script>
<script>
function showResult() {
var form = $('example');
form.focusFirstElement();
}
</script>
</head>
<body>
<p>单击按钮查看结果。</p>
<br />
<form id = "example" action = "#" onsubmit = "return false">
<fieldset>
<legend>User info</legend>
<div>
<label for = "username">Username:</label>
<input name = "username" id = "username" value = "Sulien" type = "text">
</div>
<div>
<label for = "age">Age:</label>
<input name = "age" id = "age" value = "23" size = "3" type = "text">
</div>
<div>
<label for = "hobbies">Your hobbies are:</label>
<select name = "hobbies" id = "hobbies" multiple = "multiple">
<option>coding</option>
<option>swimming</option>
<option>hiking</option>
<option>drawing</option>
</select>
</div>
</fieldset>
</form>
<br />
<input type = "button" value = "Result" onclick = "showResult();"/>
</body>
</html>
输出
prototype_form_management.html
