hostenv_browser.js

对java中如何使用Ajax技术

/*
	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
*/

if(typeof window != 'undefined'){

	// attempt to figure out the path to dojo if it isn't set in the config
	(function(){
		// before we get any further with the config options, try to pick them out
		// of the URL. Most of this code is from NW
		if(djConfig.allowQueryConfig){
			var baseUrl = document.location.toString(); // FIXME: use location.query instead?
			var params = baseUrl.split("?", 2);
			if(params.length > 1){
				var paramStr = params[1];
				var pairs = paramStr.split("&");
				for(var x in pairs){
					var sp = pairs[x].split("=");
					// FIXME: is this eval dangerous?
					if((sp[0].length > 9)&&(sp[0].substr(0, 9) == "djConfig.")){
						var opt = sp[0].substr(9);
						try{
							djConfig[opt]=eval(sp[1]);
						}catch(e){
							djConfig[opt]=sp[1];
						}
					}
				}
			}
		}

		if(
			((djConfig["baseScriptUri"] == "")||(djConfig["baseRelativePath"] == "")) && 
			(document && document.getElementsByTagName)
		){
			var scripts = document.getElementsByTagName("script");
			var rePkg = /(__package__|dojo|bootstrap1)\.js([\?\.]|$)/i;
			for(var i = 0; i < scripts.length; i++) {
				var src = scripts[i].getAttribute("src");
				if(!src) { continue; }
				var m = src.match(rePkg);
				if(m) {
					var root = src.substring(0, m.index);
					if(src.indexOf("bootstrap1") > -1) { root += "../"; }
					if(!this["djConfig"]) { djConfig = {}; }
					if(djConfig["baseScriptUri"] == "") { djConfig["baseScriptUri"] = root; }
					if(djConfig["baseRelativePath"] == "") { djConfig["baseRelativePath"] = root; }
					break;
				}
			}
		}

		// fill in the rendering support information in dojo.render.*
		var dr = dojo.render;
		var drh = dojo.render.html;
		var drs = dojo.render.svg;
		var dua = (drh.UA = navigator.userAgent);
		var dav = (drh.AV = navigator.appVersion);
		var t = true;
		var f = false;
		drh.capable = t;
		drh.support.builtin = t;

		dr.ver = parseFloat(drh.AV);
		dr.os.mac = dav.indexOf("Macintosh") >= 0;
		dr.os.win = dav.indexOf("Windows") >= 0;
		// could also be Solaris or something, but it's the same browser
		dr.os.linux = dav.indexOf("X11") >= 0;

		drh.opera = dua.indexOf("Opera") >= 0;
		drh.khtml = (dav.indexOf("Konqueror") >= 0)||(dav.indexOf("Safari") >= 0);
		drh.safari = dav.indexOf("Safari") >= 0;
		var geckoPos = dua.indexOf("Gecko");
		drh.mozilla = drh.moz = (geckoPos >= 0)&&(!drh.khtml);
		if (drh.mozilla) {
			// gecko version is YYYYMMDD
			drh.geckoVersion = dua.substring(geckoPos + 6, geckoPos + 14);
		}
		drh.ie = (document.all)&&(!drh.opera);
		drh.ie50 = drh.ie && dav.indexOf("MSIE 5.0")>=0;
		drh.ie55 = drh.ie && dav.indexOf("MSIE 5.5")>=0;
		drh.ie60 = drh.ie && dav.indexOf("MSIE 6.0")>=0;
		drh.ie70 = drh.ie && dav.indexOf("MSIE 7.0")>=0;

		var cm = document["compatMode"];
		drh.quirks = (cm == "BackCompat")||(cm == "QuirksMode")||drh.ie55||drh.ie50;

		// TODO: is the HTML LANG attribute relevant?
		dojo.locale = dojo.locale || (drh.ie ? navigator.userLanguage : navigator.language).toLowerCase();

		dr.vml.capable=drh.ie;
		drs.capable = f;
		drs.support.plugin = f;
		drs.support.builtin = f;
		var tdoc = window["document"];
		var tdi = tdoc["implementation"];

		if((tdi)&&(tdi["hasFeature"])&&(tdi.hasFeature("org.w3c.dom.svg", "1.0"))){
			drs.capable = t;
			drs.support.builtin = t;
			drs.support.plugin = f;
		}
		// webkits after 420 support SVG natively. The test string is "AppleWebKit/420+"
		if(drh.safari){
			var tmp = dua.split("AppleWebKit/")[1];
			var ver = parseFloat(tmp.split(" ")[0]);
			if(ver >= 420){
				drs.capable = t;
				drs.support.builtin = t;
				drs.support.plugin = f;
			}
		}else{
		}
	})();

	dojo.hostenv.startPackage("dojo.hostenv");

	dojo.render.name = dojo.hostenv.name_ = 'browser';
	dojo.hostenv.searchIds = [];

	// These are in order of decreasing likelihood; this will change in time.
	dojo.hostenv._XMLHTTP_PROGIDS = ['Msxml2.XMLHTTP', 'Microsoft.XMLHTTP', 'Msxml2.XMLHTTP.4.0'];

	dojo.hostenv.getXmlhttpObject = function(){
		// summary: does the work of portably generating a new XMLHTTPRequest object.
		var http = null;
		var last_e = null;
		try{ http = new XMLHttpRequest(); }catch(e){}
		if(!http){
			for(var i=0; i<3; ++i){
				var progid = dojo.hostenv._XMLHTTP_PROGIDS[i];
				try{
					http = new ActiveXObject(progid);
				}catch(e){
					last_e = e;
				}

				if(http){
					dojo.hostenv._XMLHTTP_PROGIDS = [progid];  // so faster next time
					break;
				}
			}

			/*if(http && !http.toString) {
				http.toString = function() { "[object XMLHttpRequest]"; }
			}*/
		}

		if(!http){
			return dojo.raise("XMLHTTP not available", last_e);
		}

		return http; // XMLHTTPRequest instance
	}

	dojo.hostenv._blockAsync = false;
	dojo.hostenv.getText = function(uri, async_cb, fail_ok){
		// summary: Read the contents of the specified uri and return those contents.
		// uri:
		//		A relative or absolute uri. If absolute, it still must be in
		//		the same "domain" as we are.
		// async_cb:
		//		If not specified, load synchronously. If specified, load
		//		asynchronously, and use async_cb as the progress handler which
		//		takes the xmlhttp object as its argument. If async_cb, this
		//		function returns null.
		// fail_ok:
		//		Default false. If fail_ok and !async_cb and loading fails,
		//		return null instead of throwing.

		// need to block async callbacks from snatching this thread as the result
		// of an async callback might call another sync XHR, this hangs khtml forever
		// hostenv._blockAsync must also be checked in BrowserIO's watchInFlight()
		// NOTE: must be declared before scope switches ie. this.getXmlhttpObject()
		if(!async_cb){ this._blockAsync = true; }

		var http = this.getXmlhttpObject();

		function isDocumentOk(http){
			var stat = http["status"];
			// allow a 304 use cache, needed in konq (is this compliant with the http spec?)
			return Boolean((!stat)||((200 <= stat)&&(300 > stat))||(stat==304));
		}

		if(async_cb){
			var _this = this, timer = null, gbl = dojo.global();
			var xhr = dojo.evalObjPath("dojo.io.XMLHTTPTransport");
			http.onreadystatechange = function(){
				if(timer){ gbl.clearTimeout(timer); timer = null; }
				if(_this._blockAsync || (xhr && xhr._blockAsync)){
					timer = gbl.setTimeout(function () { http.onreadystatechange.apply(this); }, 10);
				}else{
					if(4==http.readyState){
						if(isDocumentOk(http)){
							// dojo.debug("LOADED URI: "+uri);
							async_cb(http.responseText);
						}
					}
				}
			}
		}

		http.open('GET', uri, async_cb ? true : false);
		try{
			http.send(null);
			if(async_cb){
				return null;
			}
			if(!isDocumentOk(http)){
				var err = Error("Unable to load "+uri+" status:"+ http.status);
				err.status = http.status;
				err.responseText = http.responseText;
				throw err;
			}
		}catch(e){
			this._blockAsync = false;
			if((fail_ok)&&(!async_cb)){
				return null;
			}else{
				throw e;
			}
		}

		this._blockAsync = false;
		return http.responseText; // String
	}

	dojo.hostenv.defaultDebugContainerId = 'dojoDebug';
	dojo.hostenv._println_buffer = [];
	dojo.hostenv._println_safe = false;
	dojo.hostenv.println = function(/*String*/line){
		// summary:
		//		prints the provided line to whatever logging container is
		//		available. If the page isn't loaded yet, the line may be added
		//		to a buffer for printing later.
		if(!dojo.hostenv._println_safe){
			dojo.hostenv._println_buffer.push(line);
		}else{
			try {
				var console = document.getElementById(djConfig.debugContainerId ?
					djConfig.debugContainerId : dojo.hostenv.defaultDebugContainerId);
				if(!console) { console = dojo.body(); }

				var div = document.createElement("div");
				div.appendChild(document.createTextNode(line));
				console.appendChild(div);
			} catch (e) {
				try{
					// safari needs the output wrapped in an element for some reason
					document.write("<div>" + line + "</div>");
				}catch(e2){
					window.status = line;
				}
			}
		}
	}

	dojo.addOnLoad(function(){
		dojo.hostenv._println_safe = true;
		while(dojo.hostenv._println_buffer.length > 0){
			dojo.hostenv.println(dojo.hostenv._println_buffer.shift());
		}
	});