Onreadystatechange In Ajax Not Working

I have a problem with the onreadystatechange when i make ajax request, it used to call the function but now it does not call the processRequest. I am not sure if I edited something

Solution 1:

This line:

if (req.readyState == 4) {

...(and the corresponding }) shouldn't be in the function you're assigning to this.doPost. E.g.:

this.doPost = function(param) {

    /// make a HTTP GET request to the URL asynchronously
    req.open("POST",url, true);
    req.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
    req.setRequestHeader("Content-length",param.length);
    req.setRequestHeader("Connection", "close");
    req.send(param);
};

I'm assuming the way you use that is:

var obj = new createAjaxObject(url, callback);
obj.doPost();

...because the code quoted never actually calls the function that does the post, but rather just assigns it to a property on this. The usual place you assign properties to this is within a constructor function, hence my using new above.

(BTW: The overwhelming convention in JavaScript code is to use initial caps on functions that are used as constructors, e.g. CreateAjaxObject [or better yet, just AjaxObject] rather than createAjaxObject.)

There are a bunch of other changes I'd make to that code, but I think that's the minimum.

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Side note: I'd recommend using a JavaScript library like jQuery, Prototype, YUI, Closure, or any of several others. They smooth over a lot of browser differences and provide a huge amount of well-tested utility functionality, letting you focus on what you actually need to do.