HTML forms.
Second, the requests themselves are asynchronous,meaning that the
contextual links, zoom control , and the other page features remain
accessible while the map is gathering new data.
The four main components of Ajax:Javascript defines business rules and
program flow. The Document Object Model and Cascading Style Sheets allow
the application to reorgnize its appearance in response to data feteched in
the background from the server by the XMLHttpRequest object or its close
cousins.
We've hightlighted a few more here , to demonstrate the breadth of concerns
to which CSS can be applied:
(1)on-screen placement
(2)texturing elements
(3)assisting in layout of elements
(4)placing text relative to accompanying graphics
The DOM presents an HTML document as a tree structure , with each element
representing a tag in the HTML markup.
Working with the DOM using Javascript
An Example:
window.onload=function(){
var hello=document.getElementById('hello');
hello.className='declared';
var empty = document.getElementById('empty');
addNode(empty,"reader of");
addNode(empty,"Ajax in action");
var children = empty.childNodes;
for (var i=0;i<children.length;i++){
children[i].className='programmed';
}
empty.style.border='solid green 2px';
empty.style.width='200px';
}
function addNode(el,text){
var childEl = document.createElement('div'); --create new element
el.appendChild(childEl);
var txtNode=document.createTextNode(txt); --create text element
childEl.appendChild(txtNode);
}
A third method worth mentioning allows us to make a shortcut through
documets that we haven't tagged with unique IDs. DOM nodes can also be
searched for based on their HTML tag type,usinf getElementByTagName(). For
example , document.getElementByTagName('UL') will return an array of all
<UL> tags in the document.
FINDING A DOM NODE
CREATING A DOM NODE
Adding styles to your document:
hello.className='declared';
empty.style.border="solid green 2px";
innerHTML
refactoring 閲嶆瀯
Working with DOM elements
A web page is exposed to Javascript through the Document Object Model
(DOM),a tree-like structure whose elements correspond to the tags of an
HTML document. When manipulating a DOM tree progarmmatically ,it is quite
common to want to find out an element's position on the page.
Unfortunately,browser vendors have provided various nonstandard methods for
doing so over the years,making it diffcult to write fail-safe cross-browser
code to accommplish the task.
window.onloadListeners = new Array();
window.addOnLoadListener(listener){
window.onloadListener[window.onloadListeners.length]=listener;
}
window.onload=function(){
for(var i=0;i<window.onloadListeners.length;i++){
var func = window.onloadListeners[i];
}
}
//------------------------------------------
Reusing user action handlers:鍛戒護妯″紡
function buttonOnClickHandler(event){
var data = new Array();
data[0]=6;
data[1]=data[0]/3;
data[2]=data[0]*data[1]+7;
var newRow = createTableRow(dataTable);
for (var i=0;i<data.length;i++){
createTableCell(newRow,data[i]);
}
}
buttonDiv.onclick=buttonOnClickHandler;
//------------------------------------
Keeping only one reference to a resource:Singleton pattern
function TradingMode(){
this.mode=MODE_RED;
}
TradingMode.prototype.setMode=function(){
}
TradingMode.instance = new TradingMode();
var TradingMode={
mode:MODE_RED,
setMode:function(){
...
}
};
鍩轟簬妯℃澘鐨勭郴緇燂細
Prototype:
Prototype鏄竴涓負Javascript緙栫▼鎻愪緵澶氱敤閫旂殑鍔╂墜綾誨簱錛屼嬌鐢ㄤ竴涓鍚戞墿灞?/P>
Javascript璇█鑷繁鏀寔涓涓狾O緙栫▼鏂瑰紡銆侾rototype鏈変竴涓湁鐗硅壊鐨凧avascript緙栫爜
鏍峰紡錛屽熀浜庤繖浜涘凡緇忓鍔犵殑璇█鐗規с傝櫧鐒禤rototype緙栫爜鑷韓寰堥毦闃呰錛屼粠Java/C#/
鏍峰紡涓縐婚櫎瀛樺湪寰堜箙浜嗭紝浣跨敤Prototype錛屽拰鍐呭緩鍦ㄥ畠涓婄殑錛屾槸鐩存帴鐨勩侾rototype
鍙互鑰冭檻涓虹被寮鍙戣呮彁渚涚被銆侫Jax搴旂敤紼嬪簭浣滆呮洿澶氬笇鏈涗嬌鐢ㄧ被寤虹珛綾昏屼笉鏄嬌鐢?/P>
Prototype鑷韓銆傛垜浠皢鏌ヨ榪欎簺綾誨湪涓嬮潰鐨勯儴鍒嗕腑銆傚湪鏈熼棿錛屼竴涓富瑕佺殑鍏充簬
Prototype鏍稿績鐨勭壒鎬ц璁哄皢甯姪浠嬬粛瀹冭嚜韜殑緙栫爜鐨勬牱寮忓拰灝嗗湪鎴戜滑璁ㄨ
Scriptaculous銆丷ico鍜孯ubt on Rail.
銆銆Prototype鍏佽涓涓璞℃墿灞曢氳繃澶嶅埗鎵鏈夌殑鐖跺璞＄殑灞炴у拰鏂規硶緇欏瓙鍏朵粬銆傝繖涓?/P>
鐗規ф槸鏈濂界殑涓句釜渚嬪瓙,璁╂垜浠湅涓涓嬪畾涔夌殑Vehicle鐖剁被
function Vehicle(numWheels,maxSpeed){
this.numWheels = numWheels;
this.maxSpeed = maxSpeed;
}
瀵規鎴戜滑鎯寵瀹氫箟涓涓簿紜殑瀹炰緥鏉ヨ〃鐜頒竴涓箻瀹㈠垪杞︺傚湪鎴戜滑鐨勫瓙綾諱腑鎴戜滑涔熸兂琛?/P>
鐜板杞︾殑鏁伴噺騫舵敮鎸佸鍔犳垨鍑忓皯鐨勬満鍒躲傚湪甯哥敤鐨凧avascript涓紝鎴戜滑鍙兘榪欐牱鍐欙細
var passTrain = new Vehicle(24,100);
passTrain.carriageCount = 12;
passTrain.addCarriage = function(){
this.carriageCount++;
}
passTrain.removeCarriage=function(){
this.carriageCount--;
}
榪欎負鎴戜滑鐨凱assTrain瀵硅薄鎻愪緵闇瑕佺殑鍔熻兘鎬с備粠璁捐鐨勮鍥劇殑鏌ョ湅榪欎簺浠ｇ爜錛岃櫧鐒跺畠
鏈夌偣鎺╅グ浜嗘墿灞曟墿灞曟у姛鑳芥у埌涓涓繛璐殑鍗曞厓銆侾rototyp鍙互鍦ㄨ繖閲屽府鍔╂垜浠紝閫?/P>
榪囧厑璁告垜浠畾涔夋墿灞曡涓轟綔涓轟竴涓璞″茍涓旀帴鐫浣跨敤瀹冩墿灞曞熀紜瀵硅薄銆傞鍏堬紝鎴戜滑浣?/P>
涓轟竴涓璞″畾涔夋墿灞曠殑鍔熻兘鎬э細
function CarriagePuller(carriageCount){
this.carriageCount = carriageCount;
this.addCarriage=function(){
this.carriageCount++;
}
this.removeCarriage=function(){
this.carriageCount--;
}
}
鎺ョ潃鎴戜滑鍚堝茍榪欎袱涓潵鏀寔涓涓璞″寘鍚墍鏈夌殑闇瑕佺殑琛屼負錛?BR>var parent = new Vehicle(24,100);
var extension = new CarriagePuller(12);
var passTrain = Object.extend(parent,extension);
娉ㄦ剰鎴戜滑鍒嗗埆鍦ㄥ紑濮嬪悗鏉ュ畾涔夌埗鍜屾墿灞曞璞★紝鎺ョ潃灝嗕粬浠繘琛屾販鍚堛傝繖鐖跺瓙鍏崇郴瀛樺湪
榪欎簺渚嬩腑錛屼笉鍦╒ehicle鍜孋arriagePuller綾諱腑銆傚綋瀹冧笉鏄紜殑緇忓吀鐨勯潰鍚戝璞★紝瀹?/P>
鍏佽鎴戜滑淇濇寔鎴戜滑浠ｇ爜涓庣郴緇熷姛鑳借繘琛屽叧鑱旓紝鍦ㄨ繖涓媺杞︽寜渚嬩腑錛屽湪涓涓湴鏂癸紝閫氳繃
鍦ㄦ垜浠洿瀹規槗榪涜澶嶇敤銆傛垜浠仛榪欎釜渚嬪瓙鐪嬭搗鏉ヤ技涔庢病鏈変粈涔堢敤澶勶紝鍦ㄥぇ鐨勯」鐩腑錛?/P>
鐢ㄨ繖縐嶆柟娉曞皝瑁呭姛鑳芥ф槸闈炲父鏈夌敤鐨勩?/P>
Prototype涔熶互AJax瀵硅薄鐨勬柟寮忔彁渚涘Ajax鏀寔錛岃繖鍙互瑙ｅ喅瓚呭鉤鍙癤MLHttpRequest瀵?/P>
璞°侫jax鏄Ajax.Request綾誨瀷鎵╁睍錛屽畠鍙互浣跨敤XMLHttpRequest鍚戞湇鍔″櫒鍙戦佽姹?/P>
錛屼緥濡傦細 var req = new Ajax.Request('myData.xml');
榪欎釜鏋勯犲瓙浣跨敤涓涓垜浠篃灝嗚鐪嬪埌鐨勫湪寰堝Prototype-based綾誨簱涓殑鏍峰紡銆傚畠浣跨敤
緇撳悎鐨勬暟緇勬潵浣滀負涓涓彲閫夌殑鍙傛暟錛屽厑璁鎬竴涓鑼冨洿鐨勬寜鐓ч渶瑕佽繘琛岄厤緗?/P>
Ajax.Updater
The View in an Ajax application
Keepling the logic out of the View 灝哣iew鍒嗙鍑簂ogic
闂存帴浣跨敤CSS澧炲姞浜嬩歡
緇戝畾浜嬩歡鎺у埗浠ｇ爜
The Rico framework has a concept of Behavior objects that target specific
sections of a DOM tree and add interactivity to them.
Keeping the view out of logic