对Dom树的操作 appendChild ,createElement,childNodes,createTextNode

window.onload=function()...{
    //????
    var hello = document.getElementById('hello');
    hello.className="declared";
    
    var empty = document.getElementById('empty');
    addNode(empty,"reader of","br"); 
    addNode(empty,"Ajax in Action","br");
  
    var children = empty.childNodes;
    for(var i=0;i<children.length;i++)...{
        children[i].className="programe";
 
    } 
    empty.style.border='solid green 2px';
    empty.style.width='200px';
}

function addNode(ele,text,br)...{
    if(text==null)...{
        ele.appendChild(document.createElement("br"));
    }else...{
        var childEl =document.createElement("div");//?????
        ele.appendChild(childEl);
    
        var txtNode = document.createTextNode(text);//?????
        childEl.appendChild(txtNode);
        if(br!=null)
            ele.appendChild(document.createElement(br));
    }
 
}

//
var i=0;

function addListItemUsingInnerHTML(ele,text)...{
    var obj = document.getElementById(ele);
    obj.innerHTML+="<div class='programe'>"+text+"</div><br>";
    
}
//

function showEmpty(ele)...{
        var obj = document.getElementById(ele);
     
        if(obj!=null)...{
        if(obj.style.display==''||obj.style.display=='inline')...{
            obj.style.display='none';
            }
        else...{
            addNode(obj,"txt"+(i++),"br");
            obj.style.display='inline';
            
            }
        }
        
    }

 

Ajax封装状态,基础

 

/**//*    
    version:0.0.1 
    Date:2007.2.11 In China
    Mail:yanweiboy@hotmail.com
    
*/

var net =new Object();//????

net.READY_STATE_UNINITIALIZED=0;
net.READY_STATE_LOADING=1;
net.READY_STATE_LOADED=2;
net.READY_STATE_INTERACTIVE=3;
net.READY_STATE_COMPLETE=4;

net.ContentLoader=function(url,onload,onerror)...{//????
    this.url=url;
    this.req=null;
    this.onload=onload;
    this.onerror=(onerror) ? onerror: this.defaultError;
    this.loadXMLDoc(url);
}

net.ContentLoader.prototype=...{
    loadXMLDoc:function(url)...{
        if(window.XMLHttpRequest)...{
            this.req=new XMLHttpRequest();
        }else if(window.ActiveXObject)...{
            this.req=new ActiveXObject("Microsoft.XMLHTTP");
        }
        if(this.req)...{
            try...{
                var loader=this;
                this.req.onreadystatechange=function()...{
                    loader.onReadyState.call(loader);
                }
                this.req.open('GET',url,true);
                this.req.send(null);
            }catch(err)...{
                this.onerror.call(this);
            }
        }
    },
    
    onReadyState:function()...{
        var req = this.req;
        var ready = req.readyState;
        
        if(ready==net.READY_STATE_COMPLETE)...{
            var httpStatus=req.status;
            if(httpStatus==200||httpStatus==0)...{
                this.onload.call(this);
            }else...{
                this.onerror.call(this);
            }
        }
    },
    
    defaultError:function()...{
        alert("error fetching data!"
            +"  readyState: "+this.req.readyState
            +"  stats: "+this.req.status
            +"  headers: "+this.req.getAllResponseHeaders()
        );
    }
    
}