Question

I’m trying to create a class that receives a URL to an XML file. It needs to then parse the XML file and save the data within member variables. Here’s a stripped down test version of what I’m trying to do:

function Test(filename) {
    this.type = "type not set";
    $(document).ready(function () {
        $.ajax({
            type: "GET", 
            url: filename, 
            dataType: "xml",
            success: function(xmlDoc) {
                var xml = $(xmlDoc)
                this.type = xml.find("type").text();                
            }       
        });
    });
}

If I run this function and then call document.writeLn(test.type), “type not set” is always printed out. If I write within the internal function that defines this.type to be the value from the xml, I see the value I expect.

I assume the issue has to do with the fact that the XML parsing needs to be done asynchronously from the actual function call. But, I can’t come up with a way of working around that.

Any help would be appreciated. Thanks.

Answer 1

Your second this refers to something else than the first this:

Try:

function Test(filename) {
    var that=this;

and then use that.type instead of this.type

also make sure that you only access the variable after the success callback has happened; you could write the code that uses the variable in a function and call that function from within success.