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Dead-simple XMLRequest framework for AJAX

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Tue. Nov. 7th, 2006 12:41 PM

1 of 1

Fordiman

ajax | http | JavaScript | XML

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This is a simple script to provide basic cross-platform XML request functionality in Javascript. It's meant to be the core component in any AJAX style framework. It is not an instantiable object, but instead is a namespaced microlibrary.

Calling is easy:
XMLRequest.GET(uri, query, callback, fallback)
uri: The location you're after
query: an associative array of form data to provide via the URL
callback: callback function of the form myCallbackFunction(objXMLHttpRequest), which is called upon successful (response = 200 OK) retrieval of the XML data
fallback: myFallbackFunction(objXMLHttpRequest), which is called upon failed (response != 200 OK) retrieval of the XML data.

XMLRequest.POST(uri, query, form, callback, fallback)
Similar, but does the query using the POST method. 'query' is the URL-appended data, still in associative array form, and 'form' is the same for the POST data.

var XMLRequest=Object();

XMLRequest.buildQuery = function (query) {

        var data="";

        var first="?";

        for (i in query) {

                data+=first+escape(i)+"="+escape(query[i]);

                first="&";

        }

        return data;

}

XMLRequest.GET = function (url, query, callback, fallback) {

        var xmlhttp=null;

        if (window.XMLHttpRequest) {

                xmlhttp=new XMLHttpRequest()

        } else if (window.ActiveXObject) {

                xmlhttp=new ActiveXObject("Microsoft.XMLHTTP")

        }

        if (xmlhttp!=null) {

                xmlhttp.onreadystatechange=function () {

                        if (xmlhttp.readyState==4) {

                                if (xmlhttp.status==200) callback(xmlhttp);

                                else fallback(xmlhttp);

                        }

                }

                var data = XMLRequest.buildQuery(query);

                xmlhttp.open("GET",url+data,true);

                xmlhttp.send("");

        }else{

                alert("Your browser does not support XMLHTTP.")

        }

}

XMLRequest.POST = function (url, query, form, callback, fallback) {

        var xmlhttp=null;

        if (window.XMLHttpRequest) {

                xmlhttp=new XMLHttpRequest()

        } else if (window.ActiveXObject) {

                xmlhttp=new ActiveXObject("Microsoft.XMLHTTP")

        }

        if (xmlhttp!=null) {

                xmlhttp.onreadystatechange=function () {

                        if (xmlhttp.readyState==4) {

                                if (xmlhttp.status==200) {

                                        callback(xmlhttp);

                                } else {

                                        fallback(xmlhttp);

                                }

                        }

                }

                var urldata = XMLRequest.buildQuery(query);

                var postdata = XMLRequest.buildQuery(form).substr(1);

                xmlhttp.open("POST",url+urldata,true);

                xmlhttp.setRequestHeader("Content-type" , "application/x-www-form-urlencoded");

                xmlhttp.setRequestHeader("Content-length", postdata.length);

                xmlhttp.setRequestHeader("Connection", "close");

                xmlhttp.send(postdata);

        }else{

                alert("Your browser does not support XMLHTTP.")

        }

}