Question

function JsonCall() {
    JsonClient.setRequestHeader("Content-type", "application/json");
    JsonClient.send(Data);     
    JsonClient.onload = function() {    
      SomeOtherFunction(this.responseText);      
    }           
}

// This function is in someother class.

    var Object = {
        SomeOtherFunction: function() {
         return data;
        }
   }

1. What will my JsonCall function
   return?
2. Can i do something where i can
   return the value from onLoad call of
   Json Object?

I want to do some logic in my other class and return the value via this JsonCall function

Answer 1

Looks odd to me. The JsonClient object is supposed to be a XHR object here. However, a XHR object offers a onreadystatechange event to handle a complete transfer by checking the readyState attribute.

The only exception is a XDomainRequest object from the Internet Explorer. That object indeed has an .onload property. Right now, your JsonCall() methods returns undefined. You would need to add a callback method to execute. Like

function JsonCall( SomeOtherFunction ) {
    JsonClient.setRequestHeader("Content-type", "application/json");
    JsonClient.send(Data);     
    JsonClient.onload = function() {    
      SomeOtherFunction(this.responseText);      
    }           
}

and then call it like

JsonCall( Object.SomeOtherFunction );

where I hope Object is just an example word here.