Response.Write(JavaScript)

Bassem · #1 June 29th, 2009, 08:20 PM

Hello everybody,
I know it is an ordinary question, I tried a lot and searched but got nothing.
I request another page (Default2.aspx) using JavaScript from (Default.aspx), get a response Response.Write() as a JavaScript then using document.write() to update the page.

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 <script language="javascript" type="text/javascript">

var xmlHttpTopologyReceiver = GetXmlHttpObject();

function GetXmlHttpObject()

{

    var xmlHttp = null;

    try

      {

          // Firefox, Opera 8.0+, Safari

          xmlHttp = new XMLHttpRequest();

      }

    catch (e)

      {

          // Internet Explorer

          try

            {

                xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");

            }

          catch (e)

            {

                xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");

            }

      }

    return xmlHttp;

}

function receiveData()

{

    if(null == xmlHttpTopologyReceiver)

    {

        alert("Your browser does not support AJAX!");

        return;

    }
 
    var url = "Default2.aspx";
 
    xmlHttpTopologyReceiver.onreadystatechange = stateChanged;

    xmlHttpTopologyReceiver.open("GET", url, true);

    xmlHttpTopologyReceiver.send(null);

}
 
function hola()

{

    alert('Hola');

}
 
function stateChanged() 

{ 

    if (xmlHttpTopologyReceiver.readyState == 4)

    {         

        var data = xmlHttpTopologyReceiver.responseText;
 
        document.write(data);

    }

}

</script>

code of Default2.aspx

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     protected void Page_Load(object sender, EventArgs e)

    {

        Response.Write("<script language=\"javascript\" type=\"text/javascript\">alert('Hello');</script>");

    }

The problem is when I replace alert('Hello'); with hola(); it does not execute.
Any help please! Thanks

acoder · #2 June 30th, 2009, 11:20 AM

Two problems:
1. Don't use document.write after the page has finished loading, otherwise it will overwrite the already loaded page.
2. When requesting JavaScript code, you need to either eval it or dynamically include via script tags (by adding to the head).

Bassem · #3 July 2nd, 2009, 07:33 PM

Thanks a lot acoder for reply.
Thanks for correcting me. I've simple question if you have a time.
1. What other possibility can I do instead of document.write() ?
2. I didn't understand well what you meant but I'm going t read about eval more, please if you can guide me with simple link in that.

Thanks,
Bassem

Bassem · #4 July 2nd, 2009, 07:44 PM

Well I just read a simple implement to eval function I'm out of my PC now but I hope it will work for me, the problem as you helped me is document.write() and I don''t know another way to implement.
I'll try more.

Dormilich · #5 July 2nd, 2009, 07:45 PM

1. so-called DOM scripting (manipulating the document tree by methods of the DOM API). a good starting point is MDC

2. to execute Javascript code it has to be parsed by the browser beforehand (which is done on page load) any Javascript inserted later is not parsed and thus not available by default.

Bassem · #6 July 2nd, 2009, 09:29 PM

Thanks a lot Dormilich.
I know my questions were so basic, but I'm getting my first steps and so lost.
I'll follow the link.
Thank you

acoder · #7 July 3rd, 2009, 11:46 AM

Quote:

Originally Posted by Bassem

2. I didn't understand well what you meant but I'm going t read about eval more, please if you can guide me with simple link in that.

eval() is not the only option. If you're sure exactly what code will be produced, then eval might be ok, but if not, it could be dangerous. As I mentioned, you can also include the code using script tags dynamically, e.g.:

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 var script = document.createElement("script");

script.type = ...

script.appendChild(document.createTextNode(theCode);

document.getElementsByTagName("head")[0].appendChild(script);

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