Javascript to preserve \f in returned value

Question

I have the following javascript which works fine for the most part. It gets the user that has logged in to the site and returns their DOMAIN\username info. The problem arises when the username starts with a letter that completes a valid escape character (eg. DOMAIN\fname). The \f gets interpolated and all kinds of terrible things happen. I have tried every sort of workaround to try and replace and/or escape/encode the '\'. The problem is the \f does not seem like it is available to process/match against. The string that gets operated on is 'DOMAINname'

// DOMAIN\myusername - this works fine
// DOMAIN\fusername  - fails
var userName='<%= Request.ServerVariables("LOGON_USER")%>';
    userName = userName.replace('DOMAIN','');
    alert("Username: " + userName);

I also see all kinds of weird behaviour if I try to do a workaround using the userName variable, I think this may be because it contains a hidden \f. I've searched high and low for a solution, can't find a thing. Tried to find out if I could remove the DOMAIN\ on the serverside but that doesn't seem available either. Does anyone have a solution or workaround? In the debugger, the initial value of the servervariable is correct but the next immediate call to that variable is wrong. So the interpolated values in the debugger look like this:

var userName='DOMAIN\fusername';
userName; // 'DOMAINusername' in debugger.

Thanks

Answer 1

If you're using ASP.net (as it looks like you are), use AjaxHelper.JavaScriptStringEncode or HttpUtility.JavaScriptStringEncode to output the string correctly.

var userName='<%= HttpUtility.JavaScriptStringEncode(Request.ServerVariables("LOGON_USER"))%>';