What's the difference between "<%" and "<%=" in embedded VBScript?

Question

I am working on a code base which as VBScript code embedded in HTML. I've noticed the following two different tags around said lines of code

<%= MyFunc(val1) %>

and

<% MyFunc(val1) %>

What is the difference in using the "=" character at the beginning of these sections?

Answer 1

<% evaluates an expression in server code but doesn't emit output.

<%= also evaluates the expression but wraps the result in Response.Write, so it produces output.

Answer 2

When you see:

<%= MyFunc() %>

it really means:

<%
Response.Write( MyFunc() )
%>

Its short hand for writting output to the response.

<%
MyFunc()
%>

The above will just run the code but won't write it to the response unless it has some Response.Write's inside the Function/Sub itself.