Can I call a javascript or vbscript function from the vb.net code side of a web form or can I call the vb function from a javascript or vbscript function? If so, what is the syntax?

Also, if I drag and drop a command button onto the web form, can I put an OnClick on the HTML side for the button. And how is this done? Sorry for all the questions, but this is the first asp.net stuff i have ever done. I don't really understand how the code side and html side react to each other.