Webbrowser Alert

Hi Vbforums!
First , I want to sorry for my bad english.
If you may help you I will be grateful to you.
I have a Visual Basic tool which intercepts the javascript alerts.
How can I intercept a javascript alert and its text?
For example a javascript alert appears , and I want to put in a Label this text : "An alert appeared!" how can i do this? :D
Please Help me !