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JavaScript手册
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onBlur
Executes JavaScript code when a blur event occurs; that is, when a form element loses focus or when a window or frame loses focus.
| 事件适用对象 | Button, Checkbox, FileUpload, Layer, Password, Radio, Reset, Select, Submit, Text, Textarea, Window | | 实现版本 | Navigator 2.0
Navigator 3.0: event handler of Button, Checkbox, FileUpload, Frame, Password, Radio, Reset, Submit, and Window |
语法
onBlur="handlerText"
参数
描述
The blur event can result from a call to the Window.blur method or from the user clicking the mouse on another object or window or tabbing with the keyboard.
For windows, frames, and framesets, onBlur specifies JavaScript code to execute when a window loses focus.
A frame's onBlur event handler overrides an onBlur event handler in the BODY tag of the document loaded into frame.
Note
In Navigator 3.0, on some platforms placing an onBlur event handler in a
FRAMESET tag has no effect.
使用的事件属性
示例
示例 1: Validate form input. In the following example, userName is a required text field. When a user attempts to leave the field, the onBlur event handler calls the required function to confirm that userName has a legal value.
<INPUT TYPE="text" VALUE="" NAME="userName"
onBlur="required(this.value)">
示例 2: Change the background color of a window. In the following example, a window's onBlur and onFocus event handlers change the window's background color depending on whether the window has focus.
<BODY BGCOLOR="lightgrey"
onBlur="document.bgColor='lightgrey'"
onFocus="document.bgColor='antiquewhite'">
示例 3: Change the background color of a frame. The following example creates four frames. The source for each frame, onblur2.html has the BODY tag with the onBlur and onFocus event handlers shown in Example 1. When the document loads, all frames are light grey. When the user clicks a frame, the onFocus event handler changes the frame's background color to antique white. The frame that loses focus is changed to light grey. Note that the onBlur and onFocus event handlers are within the BODY tag, not the FRAME tag.
<FRAMESET ROWS="50%,50%" COLS="40%,60%">
<FRAME SRC=onblur2.html NAME="frame1">
<FRAME SRC=onblur2.html NAME="frame2">
<FRAME SRC=onblur2.html NAME="frame3">
<FRAME SRC=onblur2.html NAME="frame4">
</FRAMESET>
The following code has the same effect as the previous code, but is implemented differently. The onFocus and onBlur event handlers are associated with the frame, not the document. The onBlur and onFocus event handlers for the frame are specified by setting the onblur and onfocus properties.
<SCRIPT>
function setUpHandlers() {
for (var i = 0; i < frames.length; i++) {
frames[i].onfocus=new Function("document.bgColor='antiquewhite'")
frames[i].onblur=new Function("document.bgColor='lightgrey'")
}
}
</SCRIPT>
<FRAMESET ROWS="50%,50%" COLS="40%,60%" onLoad=setUpHandlers()>
<FRAME SRC=onblur2.html NAME="frame1">
<FRAME SRC=onblur2.html NAME="frame2">
<FRAME SRC=onblur2.html NAME="frame3">
<FRAME SRC=onblur2.html NAME="frame4">
</FRAMESET>
示例 4: Close a window. In the following example, a window's onBlur event handler closes the window when the window loses focus.
<BODY onBlur="window.close()">
This is some text
</BODY>
参看
onChange, onFocus
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。
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