Synchronous XMLHttpRequest blocks earlier performed functions.

[Haroldp]

Because I need to be sure that an Http Request is finished before other requests can be done I am using a synchronous XML Http Request.

I want to show the text "loading..." on the page before the http-request starts. The strange thing here is that this "loading..." text is not visible on the page, but its method is performed though.

If I place an "alert('something')" in between I do see the "loading..." on the page before the alert is popping up.

How can I achieve to see the loading before the request instead of after the response of the request?

Thanks in advance...

Harold

[dmjpro]

Welcome to TSDN.

where u putting the test Loading
just send that code .....

[Haroldp]

When clicked on the row element this must be performed:

row.onclick = function()
 (
 
        LoadingData("LoadingTable");
        passData = "SessionId=" + SessionId + "&Level=" + "User");
        var XMLResponse = SynchCall("wSetMainSelection", passData);
        OnResponse(XMLResponse.documentElement.childNodes[0].data);
 }

The funcion SynchCall is as follows:

function SynchCall(method, passData)
{
 
   //alert("no matter what");
 
    url = "http://" + location.host + "/project/webservice/Access.asmx/" + method;
    if (window.XMLHttpRequest) 
    {
        xmlhttp=new XMLHttpRequest();
    } 
    else 
    {
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");  
    }  
    if (xmlhttp) 
    {    
        xmlhttp.open("POST", url, false);
        xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
        xmlhttp.send(passData);
        return xmlhttp.responseXML;
    } 
    else 
    {
        alert("Not able to create HTTP request");
    }
}

You see that the alert is commented out. If I enable it, the LoadingData function will be performed.

[Haroldp]

This code is more clear:

When clicked on the row element this must be performed:

row.onclick = function()
 (
 
        LoadingData("LoadingDiv");
        passData = "SessionId=" + SessionId + "&Level=" + "User");
        var XMLResponse = SynchCall("wSetMainSelection", passData);
        OnResponse(XMLResponse.documentElement.childNodes[0].data);
 }
 
LoadingData(div)
{
  document.getElementById(div).innerHTML = "Loading...";
}
 

The function SynchCall is as follows:

function SynchCall(method, passData)
{
 
   //alert("no matter what");
 
    url = "http://" + location.host + "/project/webservice/Access.asmx/" + method;
    if (window.XMLHttpRequest) 
    {
        xmlhttp=new XMLHttpRequest();
    } 
    else 
    {
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");  
    }  
    if (xmlhttp) 
    {    
        xmlhttp.open("POST", url, false);
        xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
        xmlhttp.send(passData);
        return xmlhttp.responseXML;
    } 
    else 
    {
        alert("Not able to create HTTP request");
    }
}

The LoadingData function will be performed always. You see that the alert is commented out. If I enable it the text "Loading..." will be shown.