JavaScript语言参考手册_事件和事件句柄 From JavaScript previous page next page JavaScript手册 目录 此参考中包含的内容 轻松上手 简介 操作符 语句 核心 文档 窗口 表单 浏览器 事件和事件句柄 LiveWire数据库服务 进程管理服务 实用工具 全局函数 LiveConnect的Java包 索引 版权 【目录】 【上一页】 【下一页】 【索引】 onFocus Executes JavaScript code when a focus event occurs; that is, when a window, frame, or frameset receives focus or when a form element receives input focus. 事件适用对象Button, Checkbox, FileUpload, Layer, Password, Radio, Reset, Select, Submit, Text, Textarea, Window实现版本Navigator 2.0Navigator 3.0: event handler of Button, Checkbox, FileUpload, Frame, Password, Radio, Reset, Submit, and WindowNavigator 4.0: event handler of Layer 语法 onFocus="handlerText" 参数 handlerTextJavaScript 代码或对一个 JavaScript 函数的调用。 描述 The focus event can result from a focus method or from the user clicking the mouse on an object or window or tabbing with the keyboard. Selecting within a field results in a select event, not a focus event. onFocus executes JavaScript code when a focus event occurs. A frame's onFocus event handler overrides an onFocus event handler in the BODY tag of the document loaded into frame. Note that placing an alert in an onFocus event handler results in recurrent alerts: when you press OK to dismiss the alert, the underlying window gains focus again and produces another focus event. Note In Navigator 3.0, on some platforms, placing an onFocus event handler in a FRAMESET tag has no effect. 使用的事件属性 type标明了事件的类型。target标明了事件原来发送的对象。 示例 The following example uses an onFocus handler in the valueField Textarea object to call the valueCheck function. <INPUT TYPE="textarea" VALUE="" NAME="valueField" onFocus="valueCheck()"> See also示例 for onBlur. 参看 onBlur, onChange 要获得关于事件句柄的常规信息，请看“事件的常规信息”。 要获得关于事件对象的信息，请看事件。 【目录】 【上一页】 【下一页】 【索引】 回页面顶部 previous page start next page
回页面顶部