Computersight -

Sometimes you need to create an AJAX request to an external domain url, which is not possible by standard means.

To create the request we will call the following function:

function crossDomainAJAX(url, callback) {
var headID = document.getElementsByTagName(”head”)[0];
var newRequest = document.createElement(’script’);

newRequest.type = ‘text/javascript’;
newRequest.language = ‘javascript’;

var schar; if (sInStr(url, “?”)==-1) { schar=”?”; } else { schar=”&”; }

newRequest.src = url + schar + ‘callback=’ + callback;

headID.appendChild(newRequest);
}

When sending the data back from the server at the external domain, we will use a function similar to this (ASP.NET VB):

Public Sub ExecuteCallback(ByVal res As String, ByVal callback As String)
Response.Write(callback & “(’” & res & “‘);”)
End Sub 

IMPORTANT: In order to successfuly run the JavaScript function, you’ll need these two auxiliary string functions:

function sMid(str, start, len) { if (start < 0 || len < 0) return “”; var iEnd, iLen = String(str).length; if (start + len > iLen) iEnd = iLen; else iEnd = start + len; return String(str).substring(start,iEnd); }
function sInStr(strSearch, charSearchFor, start) { if (!start) start=0; for (i=start; i < strSearch.length; i++) { if (charSearchFor == sMid(strSearch, i, charSearchFor.length)) {return i;} } return -1; }

Good Luck!