hacks_2_1.js

Ajax.Hacks,快来看啊

var formObj = null;
var formObjTyp = "";
var request=null;

//input field's event handlers
window.onload=function(){
    var txtA = document.getElementById("tarea");
    if(txtA != null){
        txtA.onblur=function(){
            if (this.value) { getInfo(this);}};    }

    var tfd = document.getElementById("tfield");
    // tfd.onblur=txtA.onblur;
    if(tfd != null){
        tfd.onblur=function(){
            if (this.value) { getInfo(this);}};  }
}

function getInfo(obj){
    if (obj == null ) { return; }
    formObj=obj;
    formObjTyp =obj.tagName;
    if(formObjTyp == "input" || formObjTyp == "INPUT"){
        formObjTyp = formObjTyp + " "+formObj.type;
    }
    formObjTyp = formObjTyp.toLowerCase();
    var url = "http://www.parkerriver.com/s/webforms?objtype="+
              encodeURIComponent(formObjTyp)+"&val="+ encodeURIComponent(obj.value);
    httpRequest("GET",url,true);
}

//event handler for XMLHttpRequest
function handleResponse(){
    try{
        if(request.readyState == 4){
            if(request.status == 200){
                var resp = request.responseText;
                if(resp != null){
                    var func = new Function("return "+resp);
                    var objt = func();
                    if(formObjTyp == "textarea"){
                        if(formObj != null){
                            formObj.value = objt.Form_field_type +" character count: "+objt.Text_length+"\nWord count: "+
                                            objt.Word_count+"\nServer info: "+objt.Server_info;
                        }
                    }  else if(formObjTyp == "input text"){
                        if(formObj != null){
                            formObj.value = objt.Form_field_type +" # characters: "+objt.Text_length+" Word count: "+objt.Word_count; }
                    }
                }
            } else {
                //request.status is 503  if the application isn't available; 
                //500 if the application has a bug
                alert(
                        "A problem occurred with communicating between the XMLHttpRequest object and the server program.");
            }
        }//end outer if
    } catch (err)   {
        alert(err.name);
        alert("It does not appear that the server is available for this application. Please"+
              " try again very soon. \nError: "+err.message);

    }
}

/* Initialize a Request object that is already constructed */
function initReq(reqType,url,bool){
    try{
        /* Specify the function that will handle the HTTP response */
        request.onreadystatechange=handleResponse;
        request.open(reqType,url,bool);
        request.send(null);
    } catch (errv) {
        alert(
                "The application cannot contact the server at the moment. "+
                "Please try again in a few seconds." );
    }
}
/* Wrapper function for constructing a Request object.
 Parameters:
  reqType: The HTTP request type such as GET or POST.
  url: The URL of the server program.
  asynch: Whether to send the request asynchronously or not. */
function httpRequest(reqType,url,asynch){
    //Mozilla-based browsers
    if(window.XMLHttpRequest){
        request = new XMLHttpRequest();
    } else if (window.ActiveXObject){
        request=new ActiveXObject("Msxml2.XMLHTTP");
        if (! request){
            request=new ActiveXObject("Microsoft.XMLHTTP");
        }
     }
    //the request could still be null if neither ActiveXObject
    //initializations succeeded
    if(request){
       initReq(reqType,url,asynch);
    }  else {
        alert("Your browser does not permit the use of all "+
        "of this application's features!");}
}