browser.js

js基本操作

/*
	Copyright (c) 2004-2006, The Dojo Foundation
	All Rights Reserved.

	Licensed under the Academic Free License version 2.1 or above OR the
	modified BSD license. For more information on Dojo licensing, see:

		http://dojotoolkit.org/community/licensing.shtml
*/

dojo.provide("dojo.event.browser");
dojo.require("dojo.event.common");

// FIXME: any particular reason this is in the global scope?
dojo._ie_clobber = new function(){
	this.clobberNodes = [];

	function nukeProp(node, prop){
		// try{ node.removeAttribute(prop); 	}catch(e){ /* squelch */ }
		try{ node[prop] = null; 			}catch(e){ /* squelch */ }
		try{ delete node[prop]; 			}catch(e){ /* squelch */ }
		// FIXME: JotLive needs this, but I'm not sure if it's too slow or not
		try{ node.removeAttribute(prop);	}catch(e){ /* squelch */ }
	}

	this.clobber = function(nodeRef){
		var na;
		var tna;
		if(nodeRef){
			tna = nodeRef.all || nodeRef.getElementsByTagName("*");
			na = [nodeRef];
			for(var x=0; x<tna.length; x++){
				// if we're gonna be clobbering the thing, at least make sure
				// we aren't trying to do it twice
				if(tna[x]["__doClobber__"]){
					na.push(tna[x]);
				}
			}
		}else{
			try{ window.onload = null; }catch(e){}
			na = (this.clobberNodes.length) ? this.clobberNodes : document.all;
		}
		tna = null;
		var basis = {};
		for(var i = na.length-1; i>=0; i=i-1){
			var el = na[i];
			try{
				if(el && el["__clobberAttrs__"]){
					for(var j=0; j<el.__clobberAttrs__.length; j++){
						nukeProp(el, el.__clobberAttrs__[j]);
					}
					nukeProp(el, "__clobberAttrs__");
					nukeProp(el, "__doClobber__");
				}
			}catch(e){ /* squelch! */};
		}
		na = null;
	}
}

if(dojo.render.html.ie){
	dojo.addOnUnload(function(){
		dojo._ie_clobber.clobber();
		try{
			if((dojo["widget"])&&(dojo.widget["manager"])){
				dojo.widget.manager.destroyAll();
			}
		}catch(e){}

		// Workaround for IE leak recommended in ticket #1727 by schallm
		if(dojo.widget){
			for(var name in dojo.widget._templateCache){
				if(dojo.widget._templateCache[name].node){
					dojo.dom.destroyNode(dojo.widget._templateCache[name].node);
					dojo.widget._templateCache[name].node = null;
					delete dojo.widget._templateCache[name].node;
				}
			}
		}

		try{ window.onload = null; }catch(e){}
		try{ window.onunload = null; }catch(e){}
		dojo._ie_clobber.clobberNodes = [];
		// CollectGarbage();
	});
}

dojo.event.browser = new function(){

	var clobberIdx = 0;

	this.normalizedEventName = function(/*String*/eventName){
		switch(eventName){
			case "CheckboxStateChange":
			case "DOMAttrModified":
			case "DOMMenuItemActive":
			case "DOMMenuItemInactive":
			case "DOMMouseScroll":
			case "DOMNodeInserted":
			case "DOMNodeRemoved":
			case "RadioStateChange":
				return eventName;
				break;
			default:
				return eventName.toLowerCase();
				break;
		}
	}
	
	this.clean = function(/*DOMNode*/node){
		// summary:
		//		removes native event handlers so that destruction of the node
		//		will not leak memory. On most browsers this is a no-op, but
		//		it's critical for manual node removal on IE.
		// node:
		//		A DOM node. All of it's children will also be cleaned.
		if(dojo.render.html.ie){ 
			dojo._ie_clobber.clobber(node);
		}
	}

	this.addClobberNode = function(/*DOMNode*/node){
		// summary:
		//		register the passed node to support event stripping
		// node:
		//		A DOM node
		if(!dojo.render.html.ie){ return; }
		if(!node["__doClobber__"]){
			node.__doClobber__ = true;
			dojo._ie_clobber.clobberNodes.push(node);
			// this might not be the most efficient thing to do, but it's
			// much less error prone than other approaches which were
			// previously tried and failed
			node.__clobberAttrs__ = [];
		}
	}

	this.addClobberNodeAttrs = function(/*DOMNode*/node, /*Array*/props){
		// summary:
		//		register the passed node to support event stripping
		// node:
		//		A DOM node to stip properties from later
		// props:
		//		A list of propeties to strip from the node
		if(!dojo.render.html.ie){ return; }
		this.addClobberNode(node);
		for(var x=0; x<props.length; x++){
			node.__clobberAttrs__.push(props[x]);
		}
	}

	this.removeListener = function(	/*DOMNode*/ node, 
									/*String*/	evtName, 
									/*Function*/fp, 
									/*Boolean*/	capture){
		// summary:
		//		clobbers the listener from the node
		// evtName:
		//		the name of the handler to remove the function from
		// node:
		//		DOM node to attach the event to
		// fp:
		//		the function to register
		// capture:
		//		Optional. should this listener prevent propigation?
		if(!capture){ var capture = false; }
		evtName = dojo.event.browser.normalizedEventName(evtName);
		if( (evtName == "onkey") || (evtName == "key") ){
			if(dojo.render.html.ie){
				this.removeListener(node, "onkeydown", fp, capture);
			}
			evtName = "onkeypress";
		}
		if(evtName.substr(0,2)=="on"){ evtName = evtName.substr(2); }
		// FIXME: this is mostly a punt, we aren't actually doing anything on IE
		if(node.removeEventListener){
			node.removeEventListener(evtName, fp, capture);
		}
	}

	this.addListener = function(/*DOMNode*/node, /*String*/evtName, /*Function*/fp, /*Boolean*/capture, /*Boolean*/dontFix){
		// summary:
		//		adds a listener to the node
		// evtName:
		//		the name of the handler to add the listener to can be either of
		//		the form "onclick" or "click"
		// node:
		//		DOM node to attach the event to
		// fp:
		//		the function to register
		// capture:
		//		Optional. Should this listener prevent propigation?
		// dontFix:
		//		Optional. Should we avoid registering a new closure around the
		//		listener to enable fixEvent for dispatch of the registered
		//		function?
		if(!node){ return; } // FIXME: log and/or bail?
		if(!capture){ var capture = false; }
		evtName = dojo.event.browser.normalizedEventName(evtName);
		if( (evtName == "onkey") || (evtName == "key") ){
			if(dojo.render.html.ie){
				this.addListener(node, "onkeydown", fp, capture, dontFix);
			}
			evtName = "onkeypress";
		}
		if(evtName.substr(0,2)!="on"){ evtName = "on"+evtName; }

		if(!dontFix){
			// build yet another closure around fp in order to inject fixEvent
			// around the resulting event
			var newfp = function(evt){
				if(!evt){ evt = window.event; }
				var ret = fp(dojo.event.browser.fixEvent(evt, this));
				if(capture){
					dojo.event.browser.stopEvent(evt);
				}
				return ret;
			}
		}else{
			newfp = fp;
		}

		if(node.addEventListener){ 
			node.addEventListener(evtName.substr(2), newfp, capture);
			return newfp;
		}else{
			if(typeof node[evtName] == "function" ){
				var oldEvt = node[evtName];
				node[evtName] = function(e){
					oldEvt(e);
					return newfp(e);
				}
			}else{
				node[evtName]=newfp;
			}
			if(dojo.render.html.ie){
				this.addClobberNodeAttrs(node, [evtName]);
			}
			return newfp;
		}
	}

	this.isEvent = function(/*Object*/obj){
		// summary: 
		//		Tries to determine whether or not the object is a DOM event.

		// FIXME: event detection hack ... could test for additional attributes
		// if necessary
		return (typeof obj != "undefined")&&(obj)&&(typeof Event != "undefined")&&(obj.eventPhase); // Boolean
		// Event does not support instanceof in Opera, otherwise:
		//return (typeof Event != "undefined")&&(obj instanceof Event);
	}

	this.currentEvent = null;
	
	this.callListener = function(/*Function*/listener, /*DOMNode*/curTarget){
		// summary:
		//		calls the specified listener in the context of the passed node
		//		with the current DOM event object as the only parameter
		// listener:
		//		the function to call
		// curTarget:
		//		the Node to call the function in the scope of
		if(typeof listener != 'function'){
			dojo.raise("listener not a function: " + listener);
		}
		dojo.event.browser.currentEvent.currentTarget = curTarget;
		return listener.call(curTarget, dojo.event.browser.currentEvent);
	}

	this._stopPropagation = function(){
		dojo.event.browser.currentEvent.cancelBubble = true; 
	}

	this._preventDefault = function(){
		dojo.event.browser.currentEvent.returnValue = false;