How to Get the Title of a HTML Page Displayed in U

Question

I need to extract the contents of the title tag from an HTML page displayed in a UIWebView. What is the most robust means of doing so?

I know I can do:

- (void)webViewDidFinishLoad:(UIWebView *)webView{
    NSString *theTitle=[webView stringByEvaluatingJavaScriptFromString:@"document.title"];
}

However, that only works if javascript is enabled.

Alternatively, I could just scan the text of the HTML code for the title but that feels a bit cumbersome and might prove fragile if the page's authors got freaky with their code. If it comes to that, what's the best method to use for processing the html text within the iPhone API?

I feel that I've forgotten something obvious. Is there a better method than these two choices?

Update:

Following from the answer to this question: UIWebView: Can You Disable Javascript? there appears to be no way to turn off Javascript in UIWebView. Therefore the Javascript method above will always work.

Answer 1

If Javascript Enabled Use this :-

NSString *theTitle=[webViewstringByEvaluatingJavaScriptFromString:@"document.title"];

If Javascript Disabled Use this :-

NSString * htmlCode = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.appcoda.com"] encoding:NSASCIIStringEncoding error:nil];
NSString * start = @"<title>";
NSRange range1 = [htmlCode rangeOfString:start];

NSString * end = @"</title>";
NSRange range2 = [htmlCode rangeOfString:end];

NSString * subString = [htmlCode substringWithRange:NSMakeRange(range1.location + 7, range2.location - range1.location - 7)];
NSLog(@"substring is %@",subString);

I Used +7 and -7 in NSMakeRange to eliminate the length of <title> i.e 7

Answer 2

Here is Swift 4 version, based on answer at here

func webViewDidFinishLoad(_ webView: UIWebView) {
    let theTitle = webView.stringByEvaluatingJavaScript(from: "document.title")
}

Answer 3

For those who just scroll down to find the answer:

- (void)webViewDidFinishLoad:(UIWebView *)webView{
    NSString *theTitle=[webView stringByEvaluatingJavaScriptFromString:@"document.title"];
}

This will always work as there is no way to turn off Javascript in UIWebView.

Answer 4

Edit: just saw you found out the answer... sheeeiiitttt

I literally just learned this! To do this, you don't even need to have it displayed in UIWebView. (But as you are using it, you can just get the URL of the current page)

Anyways, here's the code and some (feeble) explanation:

    //create a URL which for the site you want to get the info from.. just replace google with whatever you want
    NSURL *currentURL = [NSURL URLWithString:@"http://www.google.com"];
    //for any exceptions/errors
    NSError *error;
    //converts the url html to a string
    NSString *htmlCode = [NSString stringWithContentsOfURL:currentURL encoding:NSASCIIStringEncoding error:&error];

So we have the HTML code, now how do we get the title? Well, in every html-based doc the title is signaled by This Is the Title So probably the easiest thing to do is to search that htmlCode string for , and for , and substring it so we get the stuff in between.

    //so let's create two strings that are our starting and ending signs
    NSString *startPoint = @"<title>";
    NSString *endPoint = @"</title>";
    //now in substringing in obj-c they're mostly based off of ranges, so we need to make some ranges
    NSRange startRange = [htmlCode rangeOfString:startPoint];
    NSRange endRange = [htmlCode rangeOfString:endPoint];
    //so what this is doing is it is finding the location in the html code and turning it
    //into two ints: the location and the length of the string
    //once we have this, we can do the substringing!
    //so just for easiness, let's make another string to have the title in
    NSString *docTitle = [htmlString substringWithRange:NSMakeRange(startRange.location + startRange.length, endRange.location)];
    NSLog(@"%@", docTitle);
    //just to print it out and see it's right

And that's really it! So basically to explain all the shenanigans going on in the docTitle, if we made a range just by saying NSMakeRange(startRange.location, endRange.location) we would get the title AND the text of startString (which is ) because the location is by the first character of the string. So in order to offset that, we just added the length of the string

Now keep in mind this code is not tested.. if there are any problems it might be a spelling error, or that I didn't/did add a pointer when i wasn't supposed to.

If the title is a little weird and not completely right, try messing around with the NSMakeRange-- I mean like add/subtract different lengths/locations of the strings --- anything that seems logical.

If you have any questions or there are any problems, feel free to ask. This my first answer on this website so sorry if it's a little disorganized

Answer 5

I dońt have experience with webviews so far but, i believe it sets it´s title to the page title, so, a trick I suggest is to use a category on webview and overwrite the setter for self.title so you add a message to one of you object or modify some property to get the title.

Could you try and tell me if it works?

Answer 6

WKWebView has 'title' property, just do it like this,

func webView(_ wv: WKWebView, didFinish navigation: WKNavigation!) {
    title = wv.title
}

I don't think UIWebView is suitable right now.