How can i add Day and Night Mode to AepubReader in ios

Question

currently iam using AepubReader for reading epub files,But i want to implement day and night mode in that?Do you know how can i implement that modes? Currently iam using following code but the problems are

1.Night mode is only effecting a particular chapter. 2.Day mode changes font the color to black.

 NSUserDefaults *userDefaults2 = [NSUserDefaults standardUserDefaults];
  [userDefaults2 setBool:NO forKey:@"cc"];
  [userDefaults2 synchronize];

  [webView setOpaque:NO];
  [webView setBackgroundColor:[UIColor blackColor]];
  //    for(int i=0;i<10;i++)
  //    {
  NSString *jsString = [[NSString alloc] initWithFormat:@"document.getElementsByTagName('html')[0].style.webkitTextFillColor= 'white'"];

  [webView stringByEvaluatingJavaScriptFromString:jsString];
  //    }

Answer 1

This code works for me

-(IBAction)night:(id)sender{

NSUserDefaults *userDefaults2 = [NSUserDefaults standardUserDefaults];
[userDefaults2 setBool:NO forKey:@"btnM1"];
[userDefaults2 synchronize];

[_webview setOpaque:NO];
[_webview setBackgroundColor:[UIColor blackColor]];
NSString *jsString = [[NSString alloc] initWithFormat:@"document.getElementsByTagName('body')[0].style.webkitTextFillColor= 'white'"];
[_webview stringByEvaluatingJavaScriptFromString:jsString];}

-(IBAction)day:(id)sender{

NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
[userDefaults setBool:YES forKey:@"btnM1"];
[userDefaults synchronize];

[_webview setOpaque:NO];
[_webview setBackgroundColor:[UIColor whiteColor]];
NSString *jsString2 = [[NSString alloc] initWithFormat:@"document.getElementsByTagName('body')[0].style.webkitTextFillColor= 'black'"];
[_webview stringByEvaluatingJavaScriptFromString:jsString2];}





- (void)webViewDidFinishLoad:(UIWebView *)webView{
NSUserDefaults *menuUserDefaults = [NSUserDefaults standardUserDefaults];

if([menuUserDefaults boolForKey:@"btnM1"]){
    [_webview setOpaque:NO];
    [_webview setBackgroundColor:[UIColor whiteColor]];
    NSString *jsString2 = [[NSString alloc] initWithFormat:@"document.getElementsByTagName('body')[0].style.webkitTextFillColor= 'black'"];
    [_webview stringByEvaluatingJavaScriptFromString:jsString2];

}

else{
    [_webview setOpaque:NO];
    [_webview setBackgroundColor:[UIColor blackColor]];
    NSString *jsString = [[NSString alloc] initWithFormat:@"document.getElementsByTagName('body')[0].style.webkitTextFillColor= 'white'"];
    [_webview stringByEvaluatingJavaScriptFromString:jsString];

}}