How do I execute Javascript with parameters using wkWebView in Objective C?

Question

I am currently trying to use:

 NSString* arg = [NSString stringWithFormat:@"ReadiumSDK.reader.openSpineItemElementCfi(%@,%@,)", val1,val2]; 
 [self executeJavaScript:arg completionHandler:nil];

but this throws an error.

Answer 1

I pass parameters into javascript functions all the time from a WkWebView:

One problem may be that your parameters need to be inside single quotes and you have an extra , at the end: "ReadiumSDK.reader.openSpineItemElementCfi('%@','%@')"

The key is calling the function the exact same way you would in a developer console in a browser:

Sample below in Chrome's developer tools I would type: SomeFunction('stringParameter')

NSString *someParameter = @"stringParameter";
NSString *javascript = [NSString stringWithFormat:@"SomeFunction('%@')", someParameter];
[wkWebView evaluateJavaScript:javascript completionHandler:^(NSString *result, NSError *error) {
    if(error != nil) {
        NSLog(@"SomeFunction Error: %@",error);
        return;
    }

    NSLog(@" SomeFunction Success");
}];