How can I call a JavaScript function after every a4j AJAX response?

Question

I am working on a web app using JSF w/Seam. I want to be able to call a JavaScript function after every ajax response. I\'m looking for a way to do this without putting an o

Answer 1

Since you are using RichFaces you can simply use this:

<a:status id="globalStatus" onstart="onRequestStart()" onstop="onRequestEnd()" />

Answer 2

I think this is what you are looking for: Using Global Ajax Handlers In jQuery

Answer 3

Using a4j:status should work, but it has to be inside an h:form tag:

<h:form id="randomForm" styleClass="edit">
        <a:status id="stateStatus"
         onstart="Richfaces.showModalPanel('waitBx'),document.getElementById('randomForm:search').disabled=true;"
         onstop="Richfaces.hideModalPanel('waitBx'),document.getElementById('randomForm:search').disabled=false;"
        styleClass="message" >
</a:status>

...... way more code  
</form> 

After every ajax call this pops up a wait picture and disables the search button.

Interestingly enough, at least in our code, this doesn't work for anything in a nested a4j:region.

Answer 4

Rewritten answer: see original answer in revision history

You could override the default send method of XMLHttpRequest with one that hijacks the readystatechange handler:

(function () 
{ 
    var xhrSend = XMLHttpRequest.prototype.send; 
    XMLHttpRequest.prototype.send = function  () 
     { 
        var handler = this.onreadystatechange; 
        this.onreadystatechange = function () 
        { 
            if (handler) {
                if (handler.handleEvent) handler.handleEvent.apply(xhr, arguments);
                else handler.apply(xhr, arguments);
            }
            if (this.readyState == 4) 
            { 
                // your oncomplete function here 
                this.onreadystatechange = handler; 
             } 
         }; 
        xhrSend.apply(this, arguments); 
    }; 
})(); 

Edit: The above function doesn't work with jQuery requests, and so potentially it could fail with other libraries as well. The revision below addresses the issue with a setTimeout hack to delay the code that overrides the handler. Of course, with jQuery, you can just use the .ajaxSuccess() global handler, but for other libraries with similar behavior, this would be useful.

(function() {
    function globalHandler() {
        if (this.readyState == 4) {
            // your oncomplete code here
        }
    }
    var xhrSend = XMLHttpRequest.prototype.send;
    XMLHttpRequest.prototype.send = function() {
        var xhr = this;
        if (xhr.addEventListener) {
            xhr.removeEventListener("readystatechange", globalHandler);
            xhr.addEventListener("readystatechange", globalHandler, false);
        }
        else {
            function readyStateChange() {
                if (handler) {
                    if (handler.handleEvent)
                        handler.handleEvent.apply(xhr, arguments);
                    else
                        handler.apply(xhr, arguments);
                }
                globalHandler.apply(xhr, arguments);
                setReadyStateChange();
            }
            function setReadyStateChange() {
                setTimeout(function() {
                    if (xhr.onreadystatechange != readyStateChange) {
                        handler = xhr.onreadystatechange;
                        xhr.onreadystatechange = readyStateChange;
                    }
                }, 1);
            }
            var handler;
            setReadyStateChange();
        }
        xhrSend.apply(xhr, arguments);
    };
})();

http://jsfiddle.net/gilly3/FuacA/5/
I tested this in IE7-9, and the latest versions of Chrome and FF