UIWebView remember usernam and password ,an autofill it [duplicate] - ios

Question

I'm building an iPhone app that is just a UIWebView of an existing mobile site that has a form-based login. When I login to the mobile site on iPhone Safari, I'm prompted to save my username/password, and it's then autofilled when I go back to the site later.
I'd like to enable the same functionality in the UIWebView, but for the life of me, I can't figure out how to do it. Any ideas?
Solution
Following Michael's basic model (see accepted answer), I was able to get this done. Here's what I did:
SETTING DATA
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType; {
//save form data
if(navigationType == UIWebViewNavigationTypeFormSubmitted) {
//grab the data from the page
NSString *username = [self.webView stringByEvaluatingJavaScriptFromString: #"document.myForm.username.value"];
NSString *password = [self.webView stringByEvaluatingJavaScriptFromString: #"document.myForm.password.value"];
//store values locally
[[NSUserDefaults standardUserDefaults] setObject:username forKey:#"username"];
[SFHFKeychainUtils storeUsername:username andPassword:password forServiceName:#"MyService" updateExisting:YES error:nil];
}
}
GETTING DATA
- (void)webViewDidFinishLoad:(UIWebView *)webView{
//verify view is on the login page of the site (simplified)
NSURL *requestURL = [self.webView.request URL];
if ([requestURL.host isEqualToString:#"www.mydomain.com"]) {
//check for stored login credentials
NSString *username = [[NSUserDefaults standardUserDefaults] objectForKey:#"username"];
if (username.length != 0 ) {
//create js strings
NSString *loadUsernameJS = [NSString stringWithFormat:#"document.myForm.username.value ='%#'", username];
NSString *password = [SFHFKeychainUtils getPasswordForUsername: username andServiceName:#"MyService" error:nil];
if (password.length == 0 ) password = #"";
NSString *loadPasswordJS = [NSString stringWithFormat:#"document.myForm.password.value ='%#'", password];
//autofill the form
[self.webView stringByEvaluatingJavaScriptFromString: loadUsernameJS];
[self.webView stringByEvaluatingJavaScriptFromString: loadPasswordJS];
}
}
}
Note that I'm using Buzz Andersen's awesome SFHFKeychainUtils package to store sensitive data to the iOs Keychain.
In order to get SFHFKeychainUtils working, you need to do a few things:
Add SFHFKeychainUtils.h and SFHFKeychainUtils.m to your project
Add the Security.framework to your project
#import <Security/Security.h> and #import "SFHFKeychainUtils.h"

Answer 1

From my looking I don't think there is an easy way to do it. Here is an idea of what might work though:
create your uiwebview
create a nsurlrequest
after your webview delegate page loaded function fires look in the request's http body
find the form for login (regex for common login forms?)
retrieve give the user the option to save it and then retrieve later