cocoa plugin calling webpage javascript

When your plug-in view is instantiated, WebKit calls the +plugInViewWithArguments: method of your view's main class.

The arguments parameter to that method is a dictionary that you can query for various information. In your case, you want the object corresponding to the WebPlugInContainerKey.

This is an object conforming to the WebPlugInContainer informal protocol. If it is not nil, you can ask this object for its -webFrame, which returns a WebFrame object. You can then ask the WebFrame object for its -webView.

You can then instantiate your plug-in and store a reference to the WebView.

YourPluginView.h:

#import <Cocoa/Cocoa.h>
#import <WebKit/WebKit.h>

@interface YourPluginView : NSView <WebPlugInViewFactory>
{
    WebView* webViewIvar;
}

- (id)initWithWebView:(WebView *)aWebView;
@end

YourPluginView.m:

//the WebPlugInViewFactory protocol required method
+ (NSView *)plugInViewWithArguments:(NSDictionary *)arguments 
{
    WebView* containerView = [[[arguments objectForKey:WebPlugInContainerKey] webFrame] webView];
    YourPluginView* view = [[self alloc] initWithWebView:containerView];
    return view;
}

- (id)initWithWebView:(WebView *)aWebView
{
    self = [super init];
    if(self)
    {
        webViewIvar = [aWebView retain];
    }
    return self;
}

- (void)dealloc
{
    [webViewIvar release];
    [super dealloc];
}