Auto Login in a UIWebView in Swift

Not sure if this is the right forum. I am trying to solve the above problem. I want to create a an Auto Login for a username and password on a UIWebView. The code is below. I have tried posting this to Stackoverflow last night and as of yet I have had no responses.

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var my_WebView: UIWebView!

override func viewDidLoad() {
super.viewDidLoad()

let myURL = NSURL(string:"http://shirtstream.com/sign-in-out");
let myURLRequest:NSURLRequest = NSURLRequest(URL: myURL!);
my_WebView.loadRequest(myURLRequest);


// Do any additional setup after loading the view, typically from a nib.

}
func webViewDidFinishLoad(webView : UIWebView)
{

let savedUsername = NSUserDefaults.standardUserDefaults().stringForKey("USERNAME")
let savedPassword = NSUserDefaults.standardUserDefaults().stringForKey("PASSWORD")

if savedUsername == nil || savedPassword == nil {return}

if ( countElements(savedUsername!) != 0 && countElements(savedPassword!) != 0) {
    let loadUsernameJS = "var inputFields = document.querySelectorAll(\"input[name='username']\"); \\ for (var i = inputFields.length >>> 0; i--;) { inputFields[i].value = \'\(savedUsername)\';}"
    let loadPasswordJS = "var inputFields = document.querySelectorAll(\"input[name='password']\"); \\ for (var i = inputFields.length >>> 0; i--;) { inputFields[i].value = \'\(savedPassword)\';}"

    self.webview.stringByEvaluatingJavaScriptFromString(loadUsernameJS)
    self.webview.stringByEvaluatingJavaScriptFromString(loadPasswordJS)
}

}

override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}

}

I want to know how best to find the answer for the above code. Any responses would be appreciated.

What exactly is the problem?