Ajax Posting problem

[zamuel]

Hey everyone.

I have a ready made project to fix where Ajax POST is used to submit information through form by a click. For some reason the post fails about every fourth time and does not save the information. Post goes through function (code below) and error (no description about error) in Firebug points to the last line of the code. The strange thing is that error occurs every time, but sometimes the post gets through. As being pretty new with Javascript Ajax I don't know how to solve this. Help would be highly appreciated and more information will be provided when required. Thanks in advance!

XHR.prototype._load = function(url,object) {
    var _this = this;
    if (window.XMLHttpRequest) {
        this.http_request = new XMLHttpRequest();
    } else if (window.ActiveXObject) { // IE
        try {
            this.http_request = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e) {
            try {
                this.http_request = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e) {}
        }
    }
 
    this.http_request.onreadystatechange = function(){_this.getRequest()};
    this.http_request.open("POST", url,true);
    this.http_request.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
    if (document.getElementById('textarea_url')){ 
    document.getElementById('textarea_url').value += url + "\n\n" + ((object!=false)?get(document.getElementById(object)):'');
    }
    this.http_request.send('xml=<root>' + ((object!=false)?get(document.getElementById(object)):'') +  '</root>');
}

[acoder]

What values are you passing to the _load() function? Can you also show the code for the get() function.

PS. please use code tags when posting code. See How to Ask a Question. Thanks.

[zamuel]

Thank you for the quick answer.

Ok, the load function is passed with URL, where it uses a PHP file to save the information to database. The 'object' is the content of the text field in the form posted.

Here is the get code:

XHR.prototype.getRequest = function() {
    if (this.http_request!=null) {
        if (this.http_request.readyState==4) {
            if (document.getElementById('textarea_code')) document.getElementById('textarea_code').value = this.http_request.responseText;
            try {
                var output = this.http_request.responseXML.documentElement;
                process(output);
            } catch(e) {
                //alert('niet goed');
            }
        }
    }
}
 

[zamuel]

Hmmmm...tried with code tags, but apparently didn't work.

[acoder]

I meant the get() function used on lines 19 and 21 in the first post.

[zamuel]

Oh yeah now I got it. Here is the code:

 
function get(obj) {
    var getstr = "";
    var i = 0;
 
    if (obj!=false && obj!=null) {
        if (obj.tagName.toUpperCase()!="INPUT" && obj.tagName.toUpperCase()!="TEXTAREA" && obj.tagName.toUpperCase()!="SELECT") {
            if (obj.tagName.toUpperCase()!="FORM") {
                for (i; i<obj.childNodes.length; i++) {
                    var oo = obj.childNodes[i];
                    if (oo.hasChildNodes() && oo.tagName.toUpperCase()!="TEXTAREA" && oo.tagName.toUpperCase()!="SELECT") {
                        getstr += get(oo);
                    }
                    getstr += get_element(oo);
                }
            } else {
                for (i; i<obj.elements.length; i++) {
                    var oo = obj.elements[i];
                    getstr += get_element(oo);
                }
            }
        } else {
            getstr += get_element(obj);
        }
        return getstr;
    }
}
 

By the way, I am not sure if I am posting this correctly by I am using code tags like ' code=javascript - /code with brackets.

[acoder]

Don't worry, the code tags are fine. What's the error message displayed in Firebug? Is the object passed an ID of an element on the page?

[zamuel]

I am pretty sure the answer is yes, it's passed as ID.

The page is basically TPL file where text field and submit button are assigned in PHP file. So the template is basically using tag like <td>[[textOpmerking]]</td> as text field identifier.

[zamuel]

The funny part with the firebug error is that it does not describe any error, just displays the red 'X' indicating that something went wrong.

[acoder]

Is the Console panel in Firebug enabled?

[zamuel]

Yes, it is enabled and showing the red text in case of POST.

In additionally the page is using other form the send emails. This form is using same posting methods and showing same failures in Javascript function's last line (which I posted in the question). As a result sometimes the mail gets send and sometimes it does not.

When I remove the last line in Javascript the error does not occur, but of course the functionality does not work either :) This is a tricky one!

[zamuel]

Ok, this problem is solved by using Jquery functionality. Problem was caused by the fact that code was executing other functions at the same time, simple "async: false" in new solution did the trick. Thanks for the help anyway.

[acoder]

Glad you got it working. An alternative to a synchronous request is to make the second request when the readyState of the first is complete (4).