Non-blocking JavaScript

Include via DOM

var js = document.createElement('script'); 
js.src = 'myscript.js'; 
var h = document.getElementsByTagName('head')[0]; 
h.appendChild(js);

Non-blocking JavaScript
  And what about my inline scripts?
  Setup a collection (registry) of inline scripts

Step 1
Inline in the <head>:

var myapp = { 
   stuff: [] 
}; 

Step 2
  Add to the registry
Instead of:
  alert('boo!');
Do:

  myapp.stuff.push(function(){ 
    alert('boo!'); 
  );

Step 3
  Execute all

var l = myapp.stuff.length;  
var l = myapp.stuff.length;  
for(var i = 0, i < l; i++) { 
myapp.stuff[i](); 
} 

Ajax in Tapestry5

在Tapestry5中使用一些简单的ajax还是比较方便的，ajax返回结果可以是JSONObject/JSONArray/Component/Block/String/ResponseStream等，可设置zone组件中的show/update这二个自定义的javascript方法实现复杂效果。

返回的Block和Component是以JSON对象形式返回，其中key必须为"content"，value即为要渲染的内容，这是用Zone组件更新页面的最基本用法。也可以将ResponseStream以"application/json"形式返回客户端，见下面例子。

Component是指org.apache.tapestry5.runtime.Component对象，可以通过ComponentSource.getPage()或者ComponentSource.getComponent()方法获取。
具体使用方法见以下例子：

import java.util.Date;
import org.apache.tapestry5.Block;
import org.apache.tapestry5.StreamResponse;
import org.apache.tapestry5.annotations.BeginRender;
import org.apache.tapestry5.annotations.Environmental;
import org.apache.tapestry5.annotations.InjectComponent;
import org.apache.tapestry5.annotations.Property;
import org.apache.tapestry5.corelib.components.BeanDisplay;
import org.apache.tapestry5.internal.services.ClientBehaviorSupport;
import org.apache.tapestry5.ioc.annotations.Inject;
import org.apache.tapestry5.json.JSONObject;
import org.apache.tapestry5.runtime.Component;
import org.apache.tapestry5.services.ComponentSource;
import org.apache.tapestry5.util.TextStreamResponse;

public class Test {

@Environmental
private ClientBehaviorSupport clientBehaviorSupport;

@Inject
@Property
private Block block;

@Inject
private ComponentSource componentSource;

@InjectComponent
private BeanDisplay beanDisplay;

@BeginRender
void begin() {
// clientBehaviorSupport.addZone("link1", "show", "update");
clientBehaviorSupport.linkZone("link1", "zone1");
}

StreamResponse onActionFromLink1() {
StreamResponse response = new TextStreamResponse("application/json", "{\"content\":\"更新zone1中原来的内容\"}");
return response;
}

JSONObject onActionFromLink2() {
return new JSONObject().put("content", "update zone2.");
}

Block onActionFromLink3() {
return block;
}

BeanDisplay onActionFromLink4() {
// return a component as ajax result.
return beanDisplay;
}

// JSONArray onActionFromLink2() {
// return new JSONArray("[{user: 'test', firstName: 'yu'}]");
// }

// Component onActionFromLink4() {
// return componentSource.getPage("Start");
// }

public Date getStr() {
return new Date();
}

}

<html xmlns:t="http://tapestry.apache.org/schema/tapestry_5_0_0.xsd">
<head>
<title>ajax in tapestry5</title>
</head>
<body>
<div style="margin-left: 50px">
zone1:<t:zone t:id="zone1">ajax</t:zone>
<t:actionLink id="link1" t:id="link1">用ajax返回ResponseStream更新zone1，此链接通过ClientBehaviorSupport关联到zone1</t:actionLink>
<br />
zone2:<t:zone t:id="zone2">ajax</t:zone>
<t:actionLink t:id="link2" t:zone="zone2">update zone2 using json Object</t:actionLink>
<br />
zone3:<t:block t:id="block">${str}</t:block>
<t:zone t:id="zone3">
<t:delegate to="block"/>
</t:zone>
<a t:type="actionlink" t:id="link3" href="#" t:zone="zone3">update zone3 using Block</a>
<br />
<t:block><t:beanDisplay t:object="this"/></t:block>
zone4:<t:zone t:id="zone4">ajax</t:zone>
<t:actionLink t:id="link4" t:zone="zone4">update zone4 using Component</t:actionLink>
</div>
</body>
</html>

Ruby Block比较

class Array
  def find
    for i in 0 ... self.length
      return self[i] if yield self[i]
    end
    return nil
  end  
end

a = [1, 2, 3, 4, 5]
puts a.find { |i| 
  i == 4  
}
# error syntax
puts a.find do |i| 
  i == 4  
end
# {...}比do...end块的结合能力强。例如：
# 
# foobar a, b do .. end   # foobar 是带块的方法
# foobar a, b { .. }      # b    成了带块的方法