Getting variable from nested function

Question

wondered whether anyone can help answer my question, I need to get the xml content from "data", as it is defined within a nested function within the yam_send function, I am trying to use return to get the variable back to the function 'GetBasicStatus' but it doesn't get all the way, can anyone shed any light on this. Sorry if this is an obvious solution, bit of a beginner I'm afraid.

function GetBasicStatus()

    {
        //do some stuff & define variable "command"
        data = yam_send(command);

        if (window.DOMParser)
        {
            parser=new DOMParser();
            xmlDoc=parser.parseFromString(data,"text/xml");
        }
        else    // Internet Explorer
        {
            xmlDoc=new ActiveXObject("Microsoft.XMLDOM");
            xmlDoc.async=false;
            xmlDoc.loadXML(data);
        }
    }

    function yam_send(str)
    {

        var xmlhttp;

        if (window.XMLHttpRequest)

        {// code for IE7+, Firefox, Chrome, Opera, Safari

        xmlhttp=new XMLHttpRequest();

        }

    else

        {
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
        }


    xmlhttp.onreadystatechange=function()
    {
        if (xmlhttp.readyState==4 && xmlhttp.status==200)
        {
            var data=xmlhttp.responseText;
            return data;
        }


    }
    xmlhttp.open("GET","test.php?str",true);
    xmlhttp.send();
    }

Thanks for the heads up Jon, that explains alot! :-)

steve mapp
– steve mapp

2012-11-05 19:43:57 +00:00
Commented Nov 5, 2012 at 19:43 — steve mapp
– steve mapp, Commented Nov 5, 2012 at 19:43

zlebnik · Accepted Answer · 2012-11-14 17:19:34Z

1

Function you'd provided as xmlhttp.onreadystatechange is a callback. It's executed when event is happened and can't return anything to "parent" function.

You can create some variable in a parent function and assign some value to it in callback. Or use parent funcation as a callback, like this:

var xmlResponse = null; //variable for usage outside of GetBasicStatus
function GetBasicStatus(data) {
    xmlResponse = data; //now you can use it.
    if (window.DOMParser)
    {
        parser=new DOMParser();
        xmlDoc=parser.parseFromString(data,"text/xml");
    }
    else    // Internet Explorer
    {
        xmlDoc=new ActiveXObject("Microsoft.XMLDOM");
        xmlDoc.async=false;
        xmlDoc.loadXML(data);
    }
}

function yam_send(str)
{
    var xmlhttp;

    if (window.XMLHttpRequest)
        {// code for IE7+, Firefox, Chrome, Opera, Safari
            xmlhttp=new XMLHttpRequest();
        }
    else
        {
            xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
        }

    xmlhttp.onreadystatechange=function()
        {
            if (xmlhttp.readyState==4 && xmlhttp.status==200)
            {
                var data=xmlhttp.responseText;
                GetBasicStatus(data);
            }
        }
    xmlhttp.open("GET","test.php?str",true);
    xmlhttp.send();
}

edited Nov 14, 2012 at 17:19

answered Nov 5, 2012 at 20:43

zlebnik

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steve mapp Over a year ago

Zlebnik Thanks for your comment; its the xmlhttp.responseText I need, how can I make use of this outside of the callback, I can use the this to assign new values to HTML elements but I need to be able to process the result in another function, I have a feeling I am just appoaching the problem from the wrong angle?

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