hack7.js

来自「ajax学习教程,方便大家加快学习速度,希望大家喜欢」· JavaScript 代码 · 共 71 行

var request;
var urlFragment="http://www.parkerriver.com/s/sender?name=guest";

function getAllHeaders(url){
    httpRequest("GET",url,true);
}

//event handler for XMLHttpRequest
function handleResponse(){
    try{
        if(request.readyState == 4){
            if(request.status == 200){
                /*All headers received as a single stringt*/
                var headers = request.getAllResponseHeaders ( );
                var div = document.getElementById("msgDisplay");
                if(div) {
                div.className="header";
                div.innerHTML="<pre>"+headers+"</pre>";
                    }
            } else {
                //request.status is 503  if the application isn't available; 500 if the application has a bug
                alert(request.status);
                alert("A problem occurred with communicating between the XMLHttpRequest object and the server program.");
            }
        }//end outer if
    } catch (err)   {
        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. "+
                "It may be a problem with cross-domain restrictions." );
    }
}

/* 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!");}
}