Calling a VBscript function

I'm trying to call a VBscript function with a button. I am trying to use onClick but it gives me a Javascript error when I try it. It seems to me that the program is looking for JavaScript and finding VBscript which makes the error.

So how do I call a VBscript function in HTML using the onClick argument? I have several buttons and functions on the form, so I can't use the "onsubmit" argument.

Thanks,
Mac

<INPUT onclick="ShowMessage()"TYPE="submit" NAME="Enter" value="Submit Query"></FORM>
<SCRIPT LANGUAGE=vbscript>

</SCRIPT>

<INPUT onclick="ShowMessage()"TYPE="submit" NAME="Enter" value="Submit Query"></FORM>
<SCRIPT LANGUAGE=vbscript>
function ShowMessage ()
'Code goes here
msgbox ("This is a message")
end function
</SCRIPT>