broadcaster


当您希望若干个元素共享一个或多个属性值时,或者当您想要多个元素对某一个状态改变做出响应是,可以使用 broadcaster。任何监视 broadcaster 的元素都会共享到 broadcaster 中的属性。比如说,假设我们有一个 broadcaster,它拥有一个 label 属性,而它的观察者们正在监视这个 label。这时如果 label 发生了改变,label 的观察者们将立刻被唤醒(update)。改变发生时,每个观察者都会收到一个 onbroadcast 事件。

对于 menuitem 或者 button 来说,如果只是为了根据功能是否可用,即时更新菜单项目的 disabled 状态,那么您应该优先考虑 command

更多内容请参考 Broadcasters and Observers XUL Tutorial.

Examples

(example needed)

Attributes

Inherited from XUL element
align, allowevents, allownegativeassertions, class, coalesceduplicatearcs, collapsed, container, containment, context, contextmenu, datasources, dir, empty, equalsize, flags, flex, height, hidden, id, insertafter, insertbefore, left, maxheight, maxwidth, menu, minheight, minwidth, mousethrough, observes, ordinal, orient, pack, persist, popup, position, preference-editable, querytype, ref, removeelement, sortDirection, sortResource, sortResource2, statustext, style, template, tooltip, tooltiptext, top, uri, wait-cursor, width

Properties

Inherited Properties
align, attributes, allowEvents, baseURI, boxObject, builder, childElementCount, childNodes, children, className, clientHeight, clientLeft, clientTop, clientWidth, collapsed, contextMenu, controllers, database, datasources, dir, firstChild, firstElementChild, flex, height, hidden, id, lastChild, lastElementChild, left, localName, maxHeight, maxWidth, menu, minHeight, minWidth, namespaceURI, nextElementSibling, nextSibling, nodeName, nodeType, nodeValue, observes, ordinal, orient, ownerDocument, pack, parentNode, persist, prefix, previousElementSibling, previousSibling, ref, resource, scrollHeight, scrollLeft, scrollTop, scrollWidth, statusText, style, tagName,textContent, tooltip, tooltipText, top, width

Methods

Inherited from XUL element
blur, click, doCommand, focus, getElementsByAttribute

Inherited from DOM element
addEventListener(), appendChild(), dispatchEvent(), getAttribute(), getAttributeNode(), getAttributeNodeNS(), getAttributeNS(), getElementsByTagName(), getElementsByTagNameNS(), hasAttribute(), hasAttributeNS(), hasAttributes(), hasChildNodes(), insertBefore(), isSupported(), normalize(), removeAttribute(), removeAttributeNode(), removeAttributeNS(), removeChild(), removeEventListener(), replaceChild(), setAttribute(), setAttributeNode(), setAttributeNodeNS(), setAttributeNS()

TBD

Document Tags and Contributors

Contributors to this page: Mhoudg
最后编辑者: Mhoudg,