I figured it out. I forgot to put the method on my form tag. Here's a quick example that works:
<html>
<body>
<form id="doccomp" name="doccomp" method="post">
check amount:<input name="checkamt" id="checkamt"/><br/>
check date:<input name="checkdate" id="checkdate"/><br/>
<input type="submit" name="OBBtn_Yes" value="Submit"/>
</form>
</body>
</html>
There is some extra stuff in there, like the form tag I don't think needs an id or name, and the input tags don't need an id, but I just pasted the exact code that I just confirmed does work.
