Microsoft AJAX Library Cheat Sheet（4）：DomEvent类

r囧r小猫 2021-12-04 06:29 207阅读 0赞

本文为翻译，英文原版的Cheat Sheet（PDF版本）在此下载：[http://aspnetresources.com/downloads/ms\_ajax\_library\_cheat\_sheets1.zip][http_aspnetresources.com_downloads_ms_ajax_library_cheat_sheets1.zip]

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注：标注有\[S\]的为静态方法，无须实例化对象即可使用。

**\[S\] addHandler (element, eventName, handler)  
\[S\] $addHandler (element, eventName, handler)**

为DOM元素添加某一事件的处理函数，事件名称应去掉“on”前缀。

注意：在事件处理函数中，this指向的是element，而不一定是发出该事件的元素。

Sys.UI.DomEvent.addHandler (element, "click", clickHandler);

// Same as $addHandler (element, "click", clickHandler);

function clickHandler (e) { … }

**\[S\] addHandlers (element, events, handlerOwner)  
\[S\] $addHandlers (element, events, handlerOwner)**

为DOM元素添加多个事件处理函数，events是一个事件处理函数的字典。

注意：在事件处理函数中，若指定了handlerOwner，那么this将指向该handlerOwner，否则将指向element。

$addHandlers ($get ("article"), {

mouseover: onMouseOver,

mouseout: onMouseOut

});

function onMouseOver (e) { this.style.backgroundColor = 'yellow'; }

function onMouseOut (e) { this.style.backgroundColor = 'white'; }

**\[S\] clearHandlers (element)  
\[S\] $clearHandlers (element)**

移除指定DOM元素所有的事件处理函数。

Sys.UI.DomEvent.clearHandlers (element);

// Same as $ clearHandlers (element);

**\[S\] removeHandler (element, eventName, handler)  
\[S\] $removeHandler (element, eventName, handler)**

为DOM元素移除指定的事件处理函数。

Sys.UI.DomEvent.removeHandler (element, "click", clickHandler);

// Same as $removeHandler (element, "click", clickHandler);

**preventDefault ()**

阻止执行默认的事件处理函数。例如若阻止了a元素的onclick事件，那么将不会引发页面导航。

$addHandler ($get ("showMoreLink"), "click", showMore);

function showMore (e) { e.preventDefault (); }

**stopPropagation ()**

阻止事件冒泡传递至父元素。

**Event对象的属性**

1.  **altKey**：判断触发事件时Alt键是否被按下。
2.  **button**：得到触发事件的鼠标按键。可选值为Sys.UI.MouseButton枚举（leftButton、middleButton和rightButton）。
3.  **charCode**：得到触发事件时的键盘按键代码。可以为Sys.UI.Key枚举（backspace, tab, enter,esc, space, pageUp, pageDown, end, home, left, up, right, down, del）。
4.  **clientX**：鼠标指针相对于文档可见区域的X坐标。
5.  **clientY**：鼠标指针相对于文档可见区域的Y坐标。
6.  **ctrlKey**：判断触发事件时Ctrl键是否被按下。
7.  **offsetX**：鼠标指针相对于触发事件元素左侧边缘的偏移位置。
8.  **offsetY**：鼠标指针相对于触发事件元素上边缘的偏移位置。
9.  **rawEvent**：原始的DOM事件。
10. **screenX**：鼠标指针相对于浏览者屏幕的X坐标。
11. **screenY**：鼠标指针相对于浏览者屏幕的Y坐标。
12. **shiftKey**：判断触发事件时Shift键是否被按下。
13. **target**：触发事件的对象。
14. **type**：事件名称（例如“click”）。

转载于:https://www.cnblogs.com/dflying/archive/2007/02/07/644073.html

[http_aspnetresources.com_downloads_ms_ajax_library_cheat_sheets1.zip]: http://aspnetresources.com/downloads/ms_ajax_library_cheat_sheets1.zip