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高手来帮忙看下,这段JS代码中的回调函数如何控制的

热度:425   发布时间:2012-03-19 22:03:05.0
高手来帮忙看下,这段JS代码中的回调函数怎么控制的
[size=18px]通过下面的这个函数,我想知道obj.responseText的值可以在客户端控制么??[/size]
HTML code
<form id="frmbox" method="post" action="/ajaxaction.php"></form>


JScript code
function AjaxSubmit() {
            var ajax = new AJAXRequest();
            ajax.postf("frmbox", Callback);
        }
function Callback(obj) 
        {
            var a = obj.responseText;
            result = 0;
            if (!isNaN(a))    result = parseInt(a);
        }
function AJAXRequest() {
    var xmlPool=[],objPool=[],AJAX=this,ac=arguments.length,av=arguments;
    var xmlVersion=["MSXML2.XMLHTTP","Microsoft.XMLHTTP"];
    var ec=emptyFun=function(){};
    av=ac>0?typeof(av[0])=="object"?av[0]:{}:{};
    var encode=$GEC(av.charset+"");
    var prop=['url','content','method','async','timeout','ontimeout','onrequeststart','onrequestend','oncomplete','onexception'];
    var defval=['','','GET',true,3600000,ec,ec,ec,ec,ec],l=prop.length;
    while(l--){this[prop[l]]=getp(av[prop[l]],defval[l]);}
    if(!getObj()) return false;
    function getp(p,d) { return p!=undefined?p:d; }
    function getObj() {
        var i,j,tmpObj;
        for(i=0,j=xmlPool.length;i<j;i++) if(xmlPool[i].readyState==0||xmlPool[i].readyState==4) return xmlPool[i];
        try { tmpObj=new XMLHttpRequest; }
        catch(e) {
            for(i=0,j=xmlVersion.length;i<j;i++) {
                try { tmpObj=new ActiveXObject(xmlVersion[i]); } catch(e2) { continue; }
                break;
            }
        }
        if(!tmpObj) return false;
        else { xmlPool[xmlPool.length]=tmpObj; return xmlPool[xmlPool.length-1]; }
    }
    function $(id){return document.getElementById(id);}
    function $N(d){var n=d*1;return(isNaN(n)?0:n);}
    function $VO(v){return(typeof(v)=="string"?(v=$(v))?v:false:v);}
    function $GID(){return((new Date)*1);}
    function $SOP(id,ct){objPool[id+""]=ct;}
    function $LOP(id){return(objPool[id+""]);}
    function $SRP(f,r,p){return(function(s){s=f(s);for(var i=0;i<r.length;i++) s=s.replace(r[i],p[i]);return(s);});}
    function $GEC(cs){
        if(cs.toUpperCase()=="UTF-8") return(encodeURIComponent);
        else return($SRP(escape,[/\+/g],["%2B"]));
    }
    function $ST(obj,text) {
        var nn=obj.nodeName.toUpperCase();
        if("INPUT|TEXTAREA|OPTION".indexOf(nn)>-1) obj.value=text;
        else try{obj.innerHTML=text;} catch(e){};
    }
    function $CB(cb) {
        if(typeof(cb)=="function") return cb;
        else {
            cb=$VO(cb);
            if(cb) return(function(obj){$ST(cb,obj.responseText);});
            else return this.oncomplete; }
    }
    function $GP(p,v,d,f) {
        var i=0;
        while(i<v.length){p[i]=v[i]?f[i]?f[i](v[i]):v[i]:d[i];i++;}
        while(i<d.length){p[i]=d[i];i++;}
    }
    function send(purl,pc,pcbf,pm,pa) {
        var ct,ctf=false,xmlObj=getObj(),ac=arguments.length,av=arguments;
        if(!xmlObj) return false;
        var pmp=pm.toUpperCase()=="POST"?true:false;
        if(!pm||!purl) return false;
        var ev={url:purl, content:pc, method:pm};
        purl+=(purl.indexOf("?")>-1?"&":"?")+"timestamp="+$GID();
        xmlObj.open(pm,purl,pa);
        AJAX.onrequeststart(ev);
        if(pmp) xmlObj.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
        ct=setTimeout(function(){ctf=true;xmlObj.abort();},AJAX.timeout);
        var rc=function() {
            if(ctf) { AJAX.ontimeout(ev); AJAX.onrequestend(ev); }
            else if(xmlObj.readyState==4) {
                ev.status=xmlObj.status;
                try{ clearTimeout(ct); } catch(e) {};
                try{ if(xmlObj.status==200) pcbf(xmlObj); else AJAX.onexception(ev); }
                catch(e) { AJAX.onexception(ev); }
                AJAX.onrequestend(ev);
            }
        }
        xmlObj.onreadystatechange=rc;
        if(pmp) xmlObj.send(pc); else xmlObj.send("");
        if(pa==false) rc();
        return true;
    }
    this.setcharset=function(cs) { encode=$GEC(cs); }
    this.get=function() {
        var p=[],av=arguments;
        $GP(p,av,[this.url,this.oncomplete],[null,$CB]);
        if(!p[0]&&!p[1]) return false;
        return(send(p[0],"",p[1],"GET",this.async));
    }
    this.update=function() {
        var p=[],purl,puo,pinv,pcnt,av=arguments;
        $GP(p,av,[this.oncomplete,this.url,-1,-1],[$CB,null,$N,$N]);
        if(p[2]==-1) p[3]=1;
        var sf=function(){send(p[1],"",p[0],"GET",AJAX.async);};
        var id=$GID();
        var cf=function(cc) {
            sf(); cc--; if(cc==0) return;
            $SOP(id,setTimeout(function(){cf(cc);},p[2]));
        }
        cf(p[3]);
        return id;
    }
    this.stopupdate=function(id) {
        clearTimeout($LOP(id));
    }
    this.post=function() {
        var p=[],av=arguments;
        $GP(p,av,[this.url,this.content,this.oncomplete],[null,null,$CB]);
        if(!p[0]&&!p[2]) return false;
        return(send(p[0],p[1],p[2],"POST",this.async));
    }
    this.postf=function() {
        var p=[],fo,vaf,pcbf,purl,pc,pm,ac=arguments.length,av=arguments;
        fo=ac>0?$VO(av[0]):false;
        if(!fo||(fo&&fo.nodeName!="FORM")) return false;
        vaf=fo.getAttribute("onvalidate");
        vaf=vaf?(typeof(vaf)=="string"?new Function(vaf):vaf):null;
        if(vaf&&!vaf()) return false;
        $GP(p,[av[1],fo.getAttribute("action"),fo.getAttribute("method")],[this.oncomplete,this.url,this.method],[$CB,null,null]);
        pcbf=p[0];purl=p[1];
        if(!pcbf&&!purl) return false;
        pc=this.formToStr(fo); if(!pc) return false;
        if(p[2].toUpperCase()=="POST")
            return(send(purl,pc,pcbf,"POST",true));
        else {
            purl+=(purl.indexOf("?")>-1?"&":"?")+pc;
            return(send(purl,"",pcbf,"GET",true));
        }
    }
    this.formToStr=function(fc) {
        var i,qs="",and="",ev="";
        for(i=0;i<fc.length;i++) {
            e=fc[i];
            if (e.name!='') {
                if (e.type=='select-one'&&e.selectedIndex>-1) ev=e.options[e.selectedIndex].value;
                else if (e.type=='checkbox' || e.type=='radio') {
                    if (e.checked==false) continue;
                    ev=e.value;
                }
                else ev=e.value;
                ev=encode(ev); qs+=and+e.name+'='+ev; and="&";
            }
        }
        return qs;
    }
}

 
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